diff --git a/boards/posix/native_sim/doc/index.rst b/boards/posix/native_sim/doc/index.rst
index 2f524829b72..7c692e2affc 100644
--- a/boards/posix/native_sim/doc/index.rst
+++ b/boards/posix/native_sim/doc/index.rst
@@ -112,7 +112,7 @@ host libC (:kconfig:option:`CONFIG_EXTERNAL_LIBC`).
      entropy, native posix entropy, :kconfig:option:`CONFIG_FAKE_ENTROPY_NATIVE_POSIX`, all
      eprom, eprom emulator, :kconfig:option:`CONFIG_EEPROM_EMULATOR`, host libC
      ethernet, eth native_posix, :kconfig:option:`CONFIG_ETH_NATIVE_POSIX`, host libC
-     flash, flash simulator, :kconfig:option:`CONFIG_FLASH_SIMULATOR`, host libC
+     flash, flash simulator, :kconfig:option:`CONFIG_FLASH_SIMULATOR`, all
      flash, host based flash access, :kconfig:option:`CONFIG_FUSE_FS_ACCESS`, host libC
      gpio, GPIO emulator, :kconfig:option:`CONFIG_GPIO_EMUL`, all
      gpio, SDL GPIO emulator, :kconfig:option:`CONFIG_GPIO_EMUL_SDL`, all
diff --git a/drivers/flash/CMakeLists.txt b/drivers/flash/CMakeLists.txt
index 181f16101db..8266c8c1619 100644
--- a/drivers/flash/CMakeLists.txt
+++ b/drivers/flash/CMakeLists.txt
@@ -18,7 +18,14 @@ zephyr_library_sources_ifdef(CONFIG_SOC_FLASH_CC13XX_CC26XX soc_flash_cc13xx_cc2
 zephyr_library_sources_ifdef(CONFIG_SOC_FLASH_TELINK_B91 soc_flash_b91.c)
 zephyr_library_sources_ifdef(CONFIG_SPI_NOR spi_nor.c)
 zephyr_library_sources_ifdef(CONFIG_NORDIC_QSPI_NOR nrf_qspi_nor.c)
-zephyr_library_sources_ifdef(CONFIG_FLASH_SIMULATOR flash_simulator.c)
+if(CONFIG_FLASH_SIMULATOR)
+  zephyr_library_sources(flash_simulator.c)
+  if(CONFIG_NATIVE_LIBRARY)
+    target_sources(native_simulator INTERFACE flash_simulator_native.c)
+  elseif(CONFIG_ARCH_POSIX)
+    zephyr_library_sources(flash_simulator_native.c)
+  endif()
+endif()
 zephyr_library_sources_ifdef(CONFIG_SPI_FLASH_AT45 spi_flash_at45.c)
 zephyr_library_sources_ifdef(CONFIG_SOC_FLASH_ITE_IT8XXX2 flash_ite_it8xxx2.c)
 zephyr_library_sources_ifdef(CONFIG_SOC_FLASH_NRF soc_flash_nrf.c)
diff --git a/drivers/flash/flash_simulator.c b/drivers/flash/flash_simulator.c
index 1f9aa83c395..9fe5d230207 100644
--- a/drivers/flash/flash_simulator.c
+++ b/drivers/flash/flash_simulator.c
@@ -19,18 +19,9 @@
 
 #ifdef CONFIG_ARCH_POSIX
 
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/mman.h>
-#include <fcntl.h>
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
-
+#include "flash_simulator_native.h"
 #include "cmdline.h"
 #include "soc.h"
-
 #define DEFAULT_FLASH_FILE_PATH "flash.bin"
 
 #endif /* CONFIG_ARCH_POSIX */
@@ -384,64 +375,22 @@ static const struct flash_driver_api flash_sim_api = {
 
 static int flash_mock_init(const struct device *dev)
 {
-	struct stat f_stat;
 	int rc;
-
 	ARG_UNUSED(dev);
 
-	if (flash_in_ram == true) {
-		mock_flash = (uint8_t *)malloc(FLASH_SIMULATOR_FLASH_SIZE);
-		if (mock_flash == NULL) {
-			posix_print_warning("Could not allocate flash in the process heap %s\n",
-					    strerror(errno));
-			return -EIO;
-		}
+	if (flash_in_ram == false && flash_file_path == NULL) {
+		flash_file_path = DEFAULT_FLASH_FILE_PATH;
+	}
+
+	rc = flash_mock_init_native(flash_in_ram, &mock_flash, FLASH_SIMULATOR_FLASH_SIZE,
+				    &flash_fd, flash_file_path, FLASH_SIMULATOR_ERASE_VALUE,
+				    flash_erase_at_start);
+
+	if (rc < 0) {
+		return -EIO;
 	} else {
-
-		if (flash_file_path == NULL) {
-			flash_file_path = DEFAULT_FLASH_FILE_PATH;
-		}
-
-		flash_fd = open(flash_file_path, O_RDWR | O_CREAT, (mode_t)0600);
-		if (flash_fd == -1) {
-			posix_print_warning("Failed to open flash device file "
-					"%s: %s\n",
-					flash_file_path, strerror(errno));
-			return -EIO;
-		}
-
-		rc = fstat(flash_fd, &f_stat);
-		if (rc) {
-			posix_print_warning("Failed to get status of flash device file "
-					"%s: %s\n",
-					flash_file_path, strerror(errno));
-			return -EIO;
-		}
-
-		if (ftruncate(flash_fd, FLASH_SIMULATOR_FLASH_SIZE) == -1) {
-			posix_print_warning("Failed to resize flash device file "
-					"%s: %s\n",
-					flash_file_path, strerror(errno));
-			return -EIO;
-		}
-
-		mock_flash = mmap(NULL, FLASH_SIMULATOR_FLASH_SIZE,
-				PROT_WRITE | PROT_READ, MAP_SHARED, flash_fd, 0);
-		if (mock_flash == MAP_FAILED) {
-			posix_print_warning("Failed to mmap flash device file "
-					"%s: %s\n",
-					flash_file_path, strerror(errno));
-			return -EIO;
-		}
+		return 0;
 	}
-
-	if ((flash_erase_at_start == true) || (flash_in_ram == true) || (f_stat.st_size == 0)) {
-		/* Erase the memory unit by pulling all bits to the configured erase value */
-		(void)memset(mock_flash, FLASH_SIMULATOR_ERASE_VALUE,
-				FLASH_SIMULATOR_FLASH_SIZE);
-	}
-
-	return 0;
 }
 
 #else
@@ -477,25 +426,9 @@ DEVICE_DT_INST_DEFINE(0, flash_init, NULL,
 
 static void flash_native_posix_cleanup(void)
 {
-	if (flash_in_ram == true) {
-		if (mock_flash != NULL) {
-			free(mock_flash);
-		}
-		return;
-	}
-
-	if ((mock_flash != MAP_FAILED) && (mock_flash != NULL)) {
-		munmap(mock_flash, FLASH_SIMULATOR_FLASH_SIZE);
-	}
-
-	if (flash_fd != -1) {
-		close(flash_fd);
-	}
-
-	if ((flash_rm_at_exit == true) && (flash_file_path != NULL)) {
-		/* We try to remove the file but do not error out if we can't */
-		(void) remove(flash_file_path);
-	}
+	flash_mock_cleanup_native(flash_in_ram, flash_fd, mock_flash,
+				  FLASH_SIMULATOR_FLASH_SIZE, flash_file_path,
+				  flash_rm_at_exit);
 }
 
 static void flash_native_posix_options(void)
diff --git a/drivers/flash/flash_simulator_native.c b/drivers/flash/flash_simulator_native.c
new file mode 100644
index 00000000000..b31e42c05e0
--- /dev/null
+++ b/drivers/flash/flash_simulator_native.c
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Part of flash simulator which interacts with the host OS
+ *
+ * When building for the native simulator, this file is built in the
+ * native simulator runner/host context, and not in Zephyr/embedded context.
+ */
+
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <string.h>
+#include <nsi_tracing.h>
+
+/*
+ * Initialize the flash buffer.
+ * And, if the content is to be kept on disk map it to the the buffer to the file.
+ *
+ * Returns -1 on failure
+ *	    0 on success
+ */
+int flash_mock_init_native(bool flash_in_ram, uint8_t **mock_flash, unsigned int size,
+			   int *flash_fd, const char *flash_file_path,
+			   unsigned int erase_value, bool flash_erase_at_start)
+{
+	struct stat f_stat;
+	int rc;
+
+	if (flash_in_ram == true) {
+		*mock_flash = (uint8_t *)malloc(size);
+		if (*mock_flash == NULL) {
+			nsi_print_warning("Could not allocate flash in the process heap %s\n",
+					    strerror(errno));
+			return -1;
+		}
+	} else {
+		*flash_fd = open(flash_file_path, O_RDWR | O_CREAT, (mode_t)0600);
+		if (*flash_fd == -1) {
+			nsi_print_warning("Failed to open flash device file "
+					"%s: %s\n",
+					flash_file_path, strerror(errno));
+			return -1;
+		}
+
+		rc = fstat(*flash_fd, &f_stat);
+		if (rc) {
+			nsi_print_warning("Failed to get status of flash device file "
+					"%s: %s\n",
+					flash_file_path, strerror(errno));
+			return -1;
+		}
+
+		if (ftruncate(*flash_fd, size) == -1) {
+			nsi_print_warning("Failed to resize flash device file "
+					"%s: %s\n",
+					flash_file_path, strerror(errno));
+			return -1;
+		}
+
+		*mock_flash = mmap(NULL, size,
+				PROT_WRITE | PROT_READ, MAP_SHARED, *flash_fd, 0);
+		if (*mock_flash == MAP_FAILED) {
+			nsi_print_warning("Failed to mmap flash device file "
+					"%s: %s\n",
+					flash_file_path, strerror(errno));
+			return -1;
+		}
+	}
+
+	if ((flash_erase_at_start == true) || (flash_in_ram == true) || (f_stat.st_size == 0)) {
+		/* Erase the memory unit by pulling all bits to the configured erase value */
+		(void)memset(*mock_flash, erase_value, size);
+	}
+
+	return 0;
+}
+
+/*
+ * If in RAM: Free the mock buffer
+ * If in disk: unmap the flash file from RAM, close the file, and if configured to do so,
+ * delete the file.
+ */
+void flash_mock_cleanup_native(bool flash_in_ram, int flash_fd, uint8_t *mock_flash,
+			       unsigned int size, const char *flash_file_path,
+			       bool flash_rm_at_exit)
+{
+
+	if (flash_in_ram == true) {
+		if (mock_flash != NULL) {
+			free(mock_flash);
+		}
+		return;
+	}
+
+	if ((mock_flash != MAP_FAILED) && (mock_flash != NULL)) {
+		munmap(mock_flash, size);
+	}
+
+	if (flash_fd != -1) {
+		close(flash_fd);
+	}
+
+	if ((flash_rm_at_exit == true) && (flash_file_path != NULL)) {
+		/* We try to remove the file but do not error out if we can't */
+		(void) remove(flash_file_path);
+	}
+}
diff --git a/drivers/flash/flash_simulator_native.h b/drivers/flash/flash_simulator_native.h
new file mode 100644
index 00000000000..a59136c1c20
--- /dev/null
+++ b/drivers/flash/flash_simulator_native.h
@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef DRIVERS_FLASH_FLASH_SIMULATOR_NATIVE_H
+#define DRIVERS_FLASH_FLASH_SIMULATOR_NATIVE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int flash_mock_init_native(bool flash_in_ram, uint8_t **mock_flash, unsigned int size,
+			   int *flash_fd, const char *flash_file_path,
+			   unsigned int erase_value, bool flash_erase_at_start);
+
+void flash_mock_cleanup_native(bool flash_in_ram, int flash_fd, uint8_t *mock_flash,
+			       unsigned int size, const char *flash_file_path,
+			       bool flash_rm_at_exit);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* DRIVERS_FLASH_FLASH_SIMULATOR_NATIVE_H */