diff --git a/samples/bluetooth/central/src/main.c b/samples/bluetooth/central/src/main.c
index c2a164cccb..9124256048 100644
--- a/samples/bluetooth/central/src/main.c
+++ b/samples/bluetooth/central/src/main.c
@@ -116,9 +116,9 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	start_scan();
 }
 
-static struct bt_conn_cb conn_callbacks = {
-		.connected = connected,
-		.disconnected = disconnected,
+BT_CONN_CB_DEFINE(conn_callbacks) = {
+	.connected = connected,
+	.disconnected = disconnected,
 };
 
 void main(void)
@@ -133,7 +133,5 @@ void main(void)
 
 	printk("Bluetooth initialized\n");
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	start_scan();
 }
diff --git a/samples/bluetooth/central_hr/src/main.c b/samples/bluetooth/central_hr/src/main.c
index a1bb7dfa0e..271e6c4652 100644
--- a/samples/bluetooth/central_hr/src/main.c
+++ b/samples/bluetooth/central_hr/src/main.c
@@ -235,7 +235,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	start_scan();
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -252,7 +252,5 @@ void main(void)
 
 	printk("Bluetooth initialized\n");
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	start_scan();
 }
diff --git a/samples/bluetooth/central_ht/src/main.c b/samples/bluetooth/central_ht/src/main.c
index 3a514a4857..68c53d2ece 100644
--- a/samples/bluetooth/central_ht/src/main.c
+++ b/samples/bluetooth/central_ht/src/main.c
@@ -258,7 +258,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	}
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -275,8 +275,6 @@ void main(void)
 
 	printk("Bluetooth initialized\n");
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	err = scan_start();
 
 	if (err) {
diff --git a/samples/bluetooth/central_iso/src/main.c b/samples/bluetooth/central_iso/src/main.c
index 4ed5ab53e8..61e17f1153 100644
--- a/samples/bluetooth/central_iso/src/main.c
+++ b/samples/bluetooth/central_iso/src/main.c
@@ -222,7 +222,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	start_scan();
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -239,8 +239,6 @@ void main(void)
 
 	printk("Bluetooth initialized\n");
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	iso_chan.ops = &iso_ops;
 	iso_chan.qos = &iso_qos;
 
diff --git a/samples/bluetooth/eddystone/src/main.c b/samples/bluetooth/eddystone/src/main.c
index b0d4bf7d87..4f4b0dbaa1 100644
--- a/samples/bluetooth/eddystone/src/main.c
+++ b/samples/bluetooth/eddystone/src/main.c
@@ -676,7 +676,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	}
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -685,7 +685,6 @@ void main(void)
 {
 	int err;
 
-	bt_conn_cb_register(&conn_callbacks);
 	k_work_init_delayable(&idle_work, idle_timeout);
 
 	/* Initialize the Bluetooth Subsystem */
diff --git a/samples/bluetooth/hci_pwr_ctrl/src/main.c b/samples/bluetooth/hci_pwr_ctrl/src/main.c
index e935b2d18b..83853caf38 100644
--- a/samples/bluetooth/hci_pwr_ctrl/src/main.c
+++ b/samples/bluetooth/hci_pwr_ctrl/src/main.c
@@ -190,7 +190,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	}
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -295,8 +295,6 @@ void main(void)
 	get_tx_power(BT_HCI_VS_LL_HANDLE_TYPE_ADV, 0, &txp_get);
 	printk("-> default TXP = %d\n", txp_get);
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	/* Wait for 5 seconds to give a chance users/testers
 	 * to check that default Tx power is indeed the one
 	 * selected in Kconfig.
diff --git a/samples/bluetooth/peripheral/src/main.c b/samples/bluetooth/peripheral/src/main.c
index 412dd4a949..35ed3ed52a 100644
--- a/samples/bluetooth/peripheral/src/main.c
+++ b/samples/bluetooth/peripheral/src/main.c
@@ -248,7 +248,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	printk("Disconnected (reason 0x%02x)\n", reason);
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -339,7 +339,6 @@ void main(void)
 	bt_ready();
 
 	bt_gatt_cb_register(&gatt_callbacks);
-	bt_conn_cb_register(&conn_callbacks);
 	bt_conn_auth_cb_register(&auth_cb_display);
 
 	vnd_ind_attr = bt_gatt_find_by_uuid(vnd_svc.attrs, vnd_svc.attr_count,
diff --git a/samples/bluetooth/peripheral_csc/src/main.c b/samples/bluetooth/peripheral_csc/src/main.c
index 40fcbc063b..83768bf44c 100644
--- a/samples/bluetooth/peripheral_csc/src/main.c
+++ b/samples/bluetooth/peripheral_csc/src/main.c
@@ -356,7 +356,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	printk("Disconnected (reason 0x%02x)\n", reason);
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -408,8 +408,6 @@ void main(void)
 
 	bt_ready();
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	while (1) {
 		k_sleep(K_SECONDS(1));
 
diff --git a/samples/bluetooth/peripheral_dis/src/main.c b/samples/bluetooth/peripheral_dis/src/main.c
index 733ef33617..3067851c54 100644
--- a/samples/bluetooth/peripheral_dis/src/main.c
+++ b/samples/bluetooth/peripheral_dis/src/main.c
@@ -40,7 +40,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	printk("Disconnected (reason 0x%02x)\n", reason);
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -96,8 +96,6 @@ void main(void)
 
 	printk("Bluetooth initialized\n");
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	err = bt_le_adv_start(BT_LE_ADV_CONN_NAME, ad, ARRAY_SIZE(ad), NULL, 0);
 	if (err) {
 		printk("Advertising failed to start (err %d)\n", err);
diff --git a/samples/bluetooth/peripheral_esp/src/main.c b/samples/bluetooth/peripheral_esp/src/main.c
index 0618da1fff..196ea58009 100644
--- a/samples/bluetooth/peripheral_esp/src/main.c
+++ b/samples/bluetooth/peripheral_esp/src/main.c
@@ -360,7 +360,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	printk("Disconnected (reason 0x%02x)\n", reason);
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -429,7 +429,6 @@ void main(void)
 
 	bt_ready();
 
-	bt_conn_cb_register(&conn_callbacks);
 	bt_conn_auth_cb_register(&auth_cb_display);
 
 	while (1) {
diff --git a/samples/bluetooth/peripheral_hids/src/main.c b/samples/bluetooth/peripheral_hids/src/main.c
index eb28f88b3c..41c5dac3ee 100644
--- a/samples/bluetooth/peripheral_hids/src/main.c
+++ b/samples/bluetooth/peripheral_hids/src/main.c
@@ -73,7 +73,7 @@ static void security_changed(struct bt_conn *conn, bt_security_t level,
 	}
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 	.security_changed = security_changed,
@@ -137,6 +137,5 @@ void main(void)
 		return;
 	}
 
-	bt_conn_cb_register(&conn_callbacks);
 	bt_conn_auth_cb_register(&auth_cb_display);
 }
diff --git a/samples/bluetooth/peripheral_hr/src/main.c b/samples/bluetooth/peripheral_hr/src/main.c
index 05319a4920..13cf692db9 100644
--- a/samples/bluetooth/peripheral_hr/src/main.c
+++ b/samples/bluetooth/peripheral_hr/src/main.c
@@ -44,7 +44,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	printk("Disconnected (reason 0x%02x)\n", reason);
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -115,7 +115,6 @@ void main(void)
 
 	bt_ready();
 
-	bt_conn_cb_register(&conn_callbacks);
 	bt_conn_auth_cb_register(&auth_cb_display);
 
 	/* Implement notification. At the moment there is no suitable way
diff --git a/samples/bluetooth/peripheral_ht/src/main.c b/samples/bluetooth/peripheral_ht/src/main.c
index baab2b3dae..eaa480f4b9 100644
--- a/samples/bluetooth/peripheral_ht/src/main.c
+++ b/samples/bluetooth/peripheral_ht/src/main.c
@@ -45,7 +45,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	printk("Disconnected (reason 0x%02x)\n", reason);
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -105,7 +105,6 @@ void main(void)
 
 	bt_ready();
 
-	bt_conn_cb_register(&conn_callbacks);
 	bt_conn_auth_cb_register(&auth_cb_display);
 
 	/* Implement indicate. At the moment there is no suitable way
diff --git a/samples/bluetooth/peripheral_iso/src/main.c b/samples/bluetooth/peripheral_iso/src/main.c
index 787d3a4669..9db6a78bab 100644
--- a/samples/bluetooth/peripheral_iso/src/main.c
+++ b/samples/bluetooth/peripheral_iso/src/main.c
@@ -44,7 +44,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	printk("Disconnected from %s (reason 0x%02x)\n", addr, reason);
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -156,8 +156,6 @@ void main(void)
 
 	printk("Bluetooth initialized\n");
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	err = bt_iso_server_register(&iso_server);
 	if (err) {
 		printk("Unable to register ISO server (err %d)\n", err);
diff --git a/samples/bluetooth/peripheral_ots/src/main.c b/samples/bluetooth/peripheral_ots/src/main.c
index 3f5c4cb4bc..2216bdf02e 100644
--- a/samples/bluetooth/peripheral_ots/src/main.c
+++ b/samples/bluetooth/peripheral_ots/src/main.c
@@ -52,9 +52,9 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	printk("Disconnected (reason %u)\n", reason);
 }
 
-static struct bt_conn_cb conn_callbacks = {
-	.connected        = connected,
-	.disconnected     = disconnected,
+BT_CONN_CB_DEFINE(conn_callbacks) = {
+	.connected = connected,
+	.disconnected = disconnected,
 };
 
 static int ots_obj_created(struct bt_ots *ots, struct bt_conn *conn,
@@ -266,8 +266,6 @@ void main(void)
 
 	printk("Starting Bluetooth Peripheral OTS example\n");
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	err = bt_enable(NULL);
 	if (err) {
 		printk("Bluetooth init failed (err %d)\n", err);
diff --git a/samples/bluetooth/peripheral_sc_only/src/main.c b/samples/bluetooth/peripheral_sc_only/src/main.c
index 99b76ad212..831c9b2860 100644
--- a/samples/bluetooth/peripheral_sc_only/src/main.c
+++ b/samples/bluetooth/peripheral_sc_only/src/main.c
@@ -78,7 +78,7 @@ static void security_changed(struct bt_conn *conn, bt_security_t level,
 	}
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 	.identity_resolved = identity_resolved,
@@ -136,7 +136,6 @@ void main(void)
 
 
 	bt_conn_auth_cb_register(&auth_cb_display);
-	bt_conn_cb_register(&conn_callbacks);
 
 	err = bt_le_adv_start(BT_LE_ADV_CONN_NAME, ad, ARRAY_SIZE(ad), NULL, 0);
 	if (err) {
diff --git a/samples/bluetooth/st_ble_sensor/src/main.c b/samples/bluetooth/st_ble_sensor/src/main.c
index b28c395073..710b4bfbc5 100644
--- a/samples/bluetooth/st_ble_sensor/src/main.c
+++ b/samples/bluetooth/st_ble_sensor/src/main.c
@@ -173,7 +173,7 @@ static void disconnected(struct bt_conn *disconn, uint8_t reason)
 	LOG_INF("Disconnected (reason %u)", reason);
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -191,7 +191,6 @@ void main(void)
 	if (err) {
 		return;
 	}
-	bt_conn_cb_register(&conn_callbacks);
 
 	/* Initialize the Bluetooth Subsystem */
 	err = bt_enable(bt_ready);
diff --git a/samples/boards/bbc_microbit/pong/src/ble.c b/samples/boards/bbc_microbit/pong/src/ble.c
index f336d86b02..fd6811a407 100644
--- a/samples/boards/bbc_microbit/pong/src/ble.c
+++ b/samples/boards/bbc_microbit/pong/src/ble.c
@@ -271,7 +271,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	}
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -534,7 +534,5 @@ void ble_init(void)
 
 	k_work_init_delayable(&ble_work, ble_timeout);
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	local_attr = &pong_svc.attrs[1];
 }
diff --git a/samples/boards/reel_board/mesh_badge/src/main.c b/samples/boards/reel_board/mesh_badge/src/main.c
index 949ad28d1a..0d1cf0d7ab 100644
--- a/samples/boards/reel_board/mesh_badge/src/main.c
+++ b/samples/boards/reel_board/mesh_badge/src/main.c
@@ -142,7 +142,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	}
 }
 
-static struct bt_conn_cb conn_cb = {
+BT_CONN_CB_DEFINE(conn_cb) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -164,7 +164,6 @@ static void bt_ready(int err)
 
 	printk("Mesh initialized\n");
 
-	bt_conn_cb_register(&conn_cb);
 	bt_conn_auth_cb_register(&auth_cb);
 
 	if (IS_ENABLED(CONFIG_SETTINGS)) {
diff --git a/samples/subsys/mgmt/mcumgr/smp_svr/src/bluetooth.c b/samples/subsys/mgmt/mcumgr/smp_svr/src/bluetooth.c
index a7cc6bae06..f67f4c221c 100644
--- a/samples/subsys/mgmt/mcumgr/smp_svr/src/bluetooth.c
+++ b/samples/subsys/mgmt/mcumgr/smp_svr/src/bluetooth.c
@@ -53,7 +53,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	k_work_submit(&advertise_work);
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -82,8 +82,6 @@ void start_smp_bluetooth(void)
 		return;
 	}
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	/* Initialize the Bluetooth mcumgr transport. */
 	smp_bt_register();
 }
diff --git a/subsys/bluetooth/shell/bt.c b/subsys/bluetooth/shell/bt.c
index e08fa8a7fa..2bf7926ee6 100644
--- a/subsys/bluetooth/shell/bt.c
+++ b/subsys/bluetooth/shell/bt.c
@@ -418,7 +418,7 @@ void le_phy_updated(struct bt_conn *conn,
 }
 #endif
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 	.le_param_req = le_param_req,
@@ -576,8 +576,6 @@ static void bt_ready(int err)
 
 #if defined(CONFIG_BT_CONN)
 	default_conn = NULL;
-
-	bt_conn_cb_register(&conn_callbacks);
 #endif /* CONFIG_BT_CONN */
 
 #if defined(CONFIG_BT_PER_ADV_SYNC)
diff --git a/subsys/bluetooth/shell/l2cap.c b/subsys/bluetooth/shell/l2cap.c
index 8792b8fbb1..90d98f72d1 100644
--- a/subsys/bluetooth/shell/l2cap.c
+++ b/subsys/bluetooth/shell/l2cap.c
@@ -184,7 +184,7 @@ static void l2cap_whitelist_remove(struct bt_conn *conn, uint8_t reason)
 	}
 }
 
-static struct bt_conn_cb l2cap_conn_callbacks = {
+BT_CONN_CB_DEFINE(l2cap_conn_callbacks) = {
 	.disconnected = l2cap_whitelist_remove,
 };
 
@@ -268,8 +268,6 @@ static int cmd_register(const struct shell *shell, size_t argc, char *argv[])
 		server.psm = 0U;
 		return -ENOEXEC;
 	} else {
-		bt_conn_cb_register(&l2cap_conn_callbacks);
-
 		shell_print(shell, "L2CAP psm %u sec_level %u registered",
 			    server.psm, server.sec_level);
 	}
diff --git a/subsys/net/l2/bluetooth/bluetooth.c b/subsys/net/l2/bluetooth/bluetooth.c
index 9e3a7579ef..1633ebe2c0 100644
--- a/subsys/net/l2/bluetooth/bluetooth.c
+++ b/subsys/net/l2/bluetooth/bluetooth.c
@@ -603,7 +603,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	default_conn = NULL;
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -615,9 +615,6 @@ static int net_bt_init(const struct device *dev)
 
 	NET_DBG("dev %p driver_data %p", dev, dev->data);
 
-#if defined(CONFIG_NET_L2_BT_MGMT)
-	bt_conn_cb_register(&conn_callbacks);
-#endif
 	err = bt_l2cap_server_register(&server);
 	if (err) {
 		return err;
diff --git a/tests/bluetooth/bsim_bt/bsim_test_advx/src/main.c b/tests/bluetooth/bsim_bt/bsim_test_advx/src/main.c
index aacbd4a6e7..4cfabaee11 100644
--- a/tests/bluetooth/bsim_bt/bsim_test_advx/src/main.c
+++ b/tests/bluetooth/bsim_bt/bsim_test_advx/src/main.c
@@ -125,7 +125,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	is_disconnected = true;
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -180,10 +180,6 @@ static void test_advx_main(void)
 	}
 	printk("success.\n");
 
-	printk("Connection callbacks register...");
-	bt_conn_cb_register(&conn_callbacks);
-	printk("success.\n");
-
 	printk("Connectable advertising...");
 	err = bt_le_adv_start(BT_LE_ADV_CONN_NAME, ad, ARRAY_SIZE(ad), NULL, 0);
 	if (err) {
@@ -1203,10 +1199,6 @@ static void test_scanx_main(void)
 	bt_le_scan_cb_register(&scan_callbacks);
 	printk("success.\n");
 
-	printk("Connection callbacks register...");
-	bt_conn_cb_register(&conn_callbacks);
-	printk("success.\n");
-
 	printk("Periodic Advertising callbacks register...");
 	bt_le_per_adv_sync_cb_register(&sync_cb);
 	printk("Success.\n");
diff --git a/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect1.c b/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect1.c
index 1642867505..2ca032c3ad 100644
--- a/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect1.c
+++ b/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect1.c
@@ -361,7 +361,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	}
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 	.le_param_updated = params_updated,
@@ -380,8 +380,6 @@ static void test_con1_main(void)
 
 	printk("Bluetooth initialized\n");
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	err = bt_le_scan_start(BT_LE_SCAN_ACTIVE, device_found);
 
 	if (err) {
diff --git a/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect2.c b/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect2.c
index c01e96e005..e2cc6621bd 100644
--- a/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect2.c
+++ b/tests/bluetooth/bsim_bt/bsim_test_app/src/test_connect2.c
@@ -97,7 +97,7 @@ static void disconnected(struct bt_conn *conn, uint8_t reason)
 	}
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -156,8 +156,6 @@ static void test_con2_main(void)
 
 	bt_ready();
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	/* Implement notification. At the moment there is no suitable way
 	 * of starting delayed work so we do it here
 	 */
diff --git a/tests/bluetooth/bsim_bt/bsim_test_audio/src/mics_client_test.c b/tests/bluetooth/bsim_bt/bsim_test_audio/src/mics_client_test.c
index cd1ae5ed01..e0e4e8b314 100644
--- a/tests/bluetooth/bsim_bt/bsim_test_audio/src/mics_client_test.c
+++ b/tests/bluetooth/bsim_bt/bsim_test_audio/src/mics_client_test.c
@@ -15,7 +15,6 @@
 #define VOCS_DESC_SIZE 64
 #define AICS_DESC_SIZE 64
 
-static struct bt_conn_cb conn_callbacks;
 extern enum bst_result_t bst_result;
 
 static struct bt_mics *mics;
@@ -222,7 +221,7 @@ static void bt_ready(int err)
 	g_bt_init = true;
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -390,7 +389,6 @@ static void test_main(void)
 		return;
 	}
 
-	bt_conn_cb_register(&conn_callbacks);
 	bt_mics_client_cb_register(&mics_cbs);
 
 	WAIT_FOR(g_bt_init);
diff --git a/tests/bluetooth/bsim_bt/bsim_test_audio/src/mics_test.c b/tests/bluetooth/bsim_bt/bsim_test_audio/src/mics_test.c
index 6eae104466..7773c157a2 100644
--- a/tests/bluetooth/bsim_bt/bsim_test_audio/src/mics_test.c
+++ b/tests/bluetooth/bsim_bt/bsim_test_audio/src/mics_test.c
@@ -137,7 +137,7 @@ static void connected(struct bt_conn *conn, uint8_t err)
 	g_is_connected = true;
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -427,8 +427,6 @@ static void test_main(void)
 		return;
 	}
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	err = bt_mics_included_get(mics, &mics_included);
 	if (err != 0) {
 		FAIL("MICS get failed (err %d)\n", err);
diff --git a/tests/bluetooth/bsim_bt/bsim_test_audio/src/vcs_client_test.c b/tests/bluetooth/bsim_bt/bsim_test_audio/src/vcs_client_test.c
index 33ff2f84af..a7b03ca75f 100644
--- a/tests/bluetooth/bsim_bt/bsim_test_audio/src/vcs_client_test.c
+++ b/tests/bluetooth/bsim_bt/bsim_test_audio/src/vcs_client_test.c
@@ -295,7 +295,7 @@ static void bt_ready(int err)
 	g_bt_init = true;
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -560,8 +560,6 @@ static void test_main(void)
 		return;
 	}
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	err = bt_vcs_client_cb_register(&vcs_cbs);
 	if (err) {
 		FAIL("CB register failed (err %d)\n", err);
diff --git a/tests/bluetooth/bsim_bt/bsim_test_audio/src/vcs_test.c b/tests/bluetooth/bsim_bt/bsim_test_audio/src/vcs_test.c
index 00efad1124..bb8c41d95a 100644
--- a/tests/bluetooth/bsim_bt/bsim_test_audio/src/vcs_test.c
+++ b/tests/bluetooth/bsim_bt/bsim_test_audio/src/vcs_test.c
@@ -201,7 +201,7 @@ static void connected(struct bt_conn *conn, uint8_t err)
 	g_is_connected = true;
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 };
@@ -675,8 +675,6 @@ static void test_main(void)
 		return;
 	}
 
-	bt_conn_cb_register(&conn_callbacks);
-
 	err = bt_vcs_included_get(vcs, &vcs_included);
 	if (err) {
 		FAIL("VCS included get failed (err %d)\n", err);
diff --git a/tests/bluetooth/bsim_bt/edtt_ble_test_app/gatt_test_app/src/main.c b/tests/bluetooth/bsim_bt/edtt_ble_test_app/gatt_test_app/src/main.c
index 8bdf9ce9e9..977fbf1c4d 100644
--- a/tests/bluetooth/bsim_bt/edtt_ble_test_app/gatt_test_app/src/main.c
+++ b/tests/bluetooth/bsim_bt/edtt_ble_test_app/gatt_test_app/src/main.c
@@ -70,7 +70,7 @@ static void security_changed(struct bt_conn *conn, bt_security_t level,
 	printk("Security changed: %s level %u\n", addr, level);
 }
 
-static struct bt_conn_cb conn_callbacks = {
+BT_CONN_CB_DEFINE(conn_callbacks) = {
 	.connected = connected,
 	.disconnected = disconnected,
 	.security_changed = security_changed,
@@ -335,7 +335,6 @@ void main(void)
 		return;
 	}
 
-	bt_conn_cb_register(&conn_callbacks);
 	bt_conn_auth_cb_register(&auth_cb_display);
 
 	/**