diff --git a/doc/releases/release-notes-4.0.rst b/doc/releases/release-notes-4.0.rst
index 9e03b3d594ae48..25ba180d581bb3 100644
--- a/doc/releases/release-notes-4.0.rst
+++ b/doc/releases/release-notes-4.0.rst
@@ -32,6 +32,9 @@ API Changes
 * Removed deprecated ``ceiling_fraction`` macro. :c:macro:`DIV_ROUND_UP` needs
   to be used now.
 
+* Deprecated ``EARLY``, ``APPLICATION`` and ``SMP`` init levels can no longer be
+  used for devices.
+
 Removed APIs in this release
 ============================
 
diff --git a/include/zephyr/device.h b/include/zephyr/device.h
index cc72cb177f3564..52b8604db8095e 100644
--- a/include/zephyr/device.h
+++ b/include/zephyr/device.h
@@ -1075,24 +1075,16 @@ device_get_dt_nodelabels(const struct device *dev)
 		Z_DEVICE_SECTION_NAME(level, prio), DEVICE_NAME_GET(dev_id)) =                     \
 		Z_DEVICE_INIT(name, pm, data, config, api, state, deps, node_id, dev_id)
 
-/* deprecated device initialization levels */
-#define Z_DEVICE_LEVEL_DEPRECATED_EARLY                                        \
-	__WARN("EARLY device driver level is deprecated")
-#define Z_DEVICE_LEVEL_DEPRECATED_PRE_KERNEL_1
-#define Z_DEVICE_LEVEL_DEPRECATED_PRE_KERNEL_2
-#define Z_DEVICE_LEVEL_DEPRECATED_POST_KERNEL
-#define Z_DEVICE_LEVEL_DEPRECATED_APPLICATION                                  \
-	__WARN("APPLICATION device driver level is deprecated")
-#define Z_DEVICE_LEVEL_DEPRECATED_SMP                                          \
-	__WARN("SMP device driver level is deprecated")
-
 /**
- * @brief Issue a warning if the given init level is deprecated.
+ * @brief Issue an error if the given init level is not supported.
  *
  * @param level Init level
  */
-#define Z_DEVICE_LEVEL_CHECK_DEPRECATED_LEVEL(level)                           \
-	Z_DEVICE_LEVEL_DEPRECATED_##level
+#define Z_DEVICE_CHECK_INIT_LEVEL(level)                                       \
+	COND_CODE_1(Z_INIT_PRE_KERNEL_1_##level, (),                           \
+	(COND_CODE_1(Z_INIT_PRE_KERNEL_2_##level, (),                          \
+	(COND_CODE_1(Z_INIT_POST_KERNEL_##level, (),                           \
+	(ZERO_OR_COMPILE_ERROR(0)))))))
 
 /**
  * @brief Define the init entry for a device.
@@ -1105,7 +1097,7 @@ device_get_dt_nodelabels(const struct device *dev)
  * @param prio Initialization priority.
  */
 #define Z_DEVICE_INIT_ENTRY_DEFINE(node_id, dev_id, init_fn_, level, prio)                         \
-	Z_DEVICE_LEVEL_CHECK_DEPRECATED_LEVEL(level)                                               \
+	Z_DEVICE_CHECK_INIT_LEVEL(level)                                                           \
                                                                                                    \
 	static const Z_DECL_ALIGN(struct init_entry) __used __noasan Z_INIT_ENTRY_SECTION(         \
 		level, prio, Z_DEVICE_INIT_SUB_PRIO(node_id))                                      \