diff --git a/homeassistant/components/saunum/config_flow.py b/homeassistant/components/saunum/config_flow.py
index b721387fd9e..20ce9f859a7 100644
--- a/homeassistant/components/saunum/config_flow.py
+++ b/homeassistant/components/saunum/config_flow.py
@@ -8,7 +8,7 @@ from typing import Any
 from pysaunum import SaunumClient, SaunumException
 import voluptuous as vol
 
-from homeassistant.config_entries import ConfigFlow, ConfigFlowResult
+from homeassistant.config_entries import SOURCE_USER, ConfigFlow, ConfigFlowResult
 from homeassistant.const import CONF_HOST
 from homeassistant.helpers import config_validation as cv
 
@@ -46,14 +46,18 @@ class LeilSaunaConfigFlow(ConfigFlow, domain=DOMAIN):
     VERSION = 1
     MINOR_VERSION = 1
 
+    async def async_step_reconfigure(
+        self, user_input: dict[str, Any] | None = None
+    ) -> ConfigFlowResult:
+        """Handle reconfiguration of the integration."""
+        return await self.async_step_user(user_input)
+
     async def async_step_user(
         self, user_input: dict[str, Any] | None = None
     ) -> ConfigFlowResult:
         """Handle the initial step."""
         errors: dict[str, str] = {}
-
         if user_input is not None:
-            # Check for duplicate configuration
             self._async_abort_entries_match(user_input)
 
             try:
@@ -64,9 +68,14 @@ class LeilSaunaConfigFlow(ConfigFlow, domain=DOMAIN):
                 _LOGGER.exception("Unexpected exception")
                 errors["base"] = "unknown"
             else:
-                return self.async_create_entry(
-                    title="Saunum",
-                    data=user_input,
+                if self.source == SOURCE_USER:
+                    return self.async_create_entry(
+                        title="Saunum",
+                        data=user_input,
+                    )
+                return self.async_update_reload_and_abort(
+                    self._get_reconfigure_entry(),
+                    data_updates=user_input,
                 )
 
         return self.async_show_form(
diff --git a/homeassistant/components/saunum/quality_scale.yaml b/homeassistant/components/saunum/quality_scale.yaml
index 95aaebae039..af6674e6d6d 100644
--- a/homeassistant/components/saunum/quality_scale.yaml
+++ b/homeassistant/components/saunum/quality_scale.yaml
@@ -45,7 +45,9 @@ rules:
   discovery:
     status: exempt
     comment: Device uses generic Espressif hardware with no unique identifying information (MAC OUI or hostname) that would distinguish it from other Espressif-based devices on the network.
-  discovery-update-info: todo
+  discovery-update-info:
+    status: exempt
+    comment: Device cannot be discovered and the Modbus TCP API does not provide MAC address or other unique network identifiers needed to update connection information.
   docs-data-update: done
   docs-examples: todo
   docs-known-limitations: done
@@ -62,7 +64,7 @@ rules:
   entity-translations: done
   exception-translations: done
   icon-translations: todo
-  reconfiguration-flow: todo
+  reconfiguration-flow: done
   repair-issues:
     status: exempt
     comment: This integration doesn't have any cases where raising an issue is needed.
diff --git a/homeassistant/components/saunum/strings.json b/homeassistant/components/saunum/strings.json
index 9b70fc45e9a..8b986423bc5 100644
--- a/homeassistant/components/saunum/strings.json
+++ b/homeassistant/components/saunum/strings.json
@@ -1,13 +1,23 @@
 {
   "config": {
     "abort": {
-      "already_configured": "[%key:common::config_flow::abort::already_configured_device%]"
+      "already_configured": "[%key:common::config_flow::abort::already_configured_device%]",
+      "reconfigure_successful": "[%key:common::config_flow::abort::reconfigure_successful%]"
     },
     "error": {
       "cannot_connect": "[%key:common::config_flow::error::cannot_connect%]",
       "unknown": "[%key:common::config_flow::error::unknown%]"
     },
     "step": {
+      "reconfigure": {
+        "data": {
+          "host": "[%key:common::config_flow::data::ip%]"
+        },
+        "data_description": {
+          "host": "[%key:component::saunum::config::step::user::data_description::host%]"
+        },
+        "description": "[%key:component::saunum::config::step::user::description%]"
+      },
       "user": {
         "data": {
           "host": "[%key:common::config_flow::data::ip%]"
diff --git a/tests/components/saunum/conftest.py b/tests/components/saunum/conftest.py
index 7c51962dbf6..b9808ab535d 100644
--- a/tests/components/saunum/conftest.py
+++ b/tests/components/saunum/conftest.py
@@ -94,3 +94,13 @@ async def init_integration(
         await hass.async_block_till_done()
 
     return mock_config_entry
+
+
+@pytest.fixture
+def mock_setup_entry() -> Generator[MagicMock]:
+    """Mock Saunum setup entry."""
+    with patch(
+        "homeassistant.components.saunum.async_setup_entry", autospec=True
+    ) as mock_setup_entry:
+        mock_setup_entry.return_value = True
+        yield mock_setup_entry
diff --git a/tests/components/saunum/test_config_flow.py b/tests/components/saunum/test_config_flow.py
index e8ab0215d6c..88ca5e4909c 100644
--- a/tests/components/saunum/test_config_flow.py
+++ b/tests/components/saunum/test_config_flow.py
@@ -2,6 +2,8 @@
 
 from __future__ import annotations
 
+from unittest.mock import AsyncMock
+
 from pysaunum import SaunumConnectionError, SaunumException
 import pytest
 
@@ -14,10 +16,11 @@ from homeassistant.data_entry_flow import FlowResultType
 from tests.common import MockConfigEntry
 
 TEST_USER_INPUT = {CONF_HOST: "192.168.1.100"}
+TEST_RECONFIGURE_INPUT = {CONF_HOST: "192.168.1.200"}
 
 
 @pytest.mark.usefixtures("mock_saunum_client")
-async def test_full_flow(hass: HomeAssistant) -> None:
+async def test_full_flow(hass: HomeAssistant, mock_setup_entry: AsyncMock) -> None:
     """Test full flow."""
     result = await hass.config_entries.flow.async_init(
         DOMAIN, context={"source": SOURCE_USER}
@@ -49,6 +52,7 @@ async def test_form_errors(
     mock_saunum_client,
     side_effect: Exception,
     error_base: str,
+    mock_setup_entry: AsyncMock,
 ) -> None:
     """Test error handling and recovery."""
     mock_saunum_client.connect.side_effect = side_effect
@@ -96,3 +100,105 @@ async def test_form_duplicate(
 
     assert result["type"] is FlowResultType.ABORT
     assert result["reason"] == "already_configured"
+
+
+@pytest.mark.usefixtures("mock_saunum_client")
+@pytest.mark.parametrize("user_input", [TEST_RECONFIGURE_INPUT, TEST_USER_INPUT])
+async def test_reconfigure_flow(
+    hass: HomeAssistant,
+    mock_config_entry: MockConfigEntry,
+    user_input: dict[str, str],
+    mock_setup_entry: AsyncMock,
+) -> None:
+    """Test reconfigure flow."""
+    mock_config_entry.add_to_hass(hass)
+
+    result = await mock_config_entry.start_reconfigure_flow(hass)
+
+    assert result["type"] is FlowResultType.FORM
+    assert result["step_id"] == "user"
+
+    result = await hass.config_entries.flow.async_configure(
+        result["flow_id"],
+        user_input,
+    )
+
+    assert result["type"] is FlowResultType.ABORT
+    assert result["reason"] == "reconfigure_successful"
+    assert mock_config_entry.data == user_input
+
+
+@pytest.mark.parametrize(
+    ("side_effect", "error_base"),
+    [
+        (SaunumConnectionError("Connection failed"), "cannot_connect"),
+        (SaunumException("Read error"), "cannot_connect"),
+        (Exception("Unexpected error"), "unknown"),
+    ],
+)
+async def test_reconfigure_errors(
+    hass: HomeAssistant,
+    mock_config_entry: MockConfigEntry,
+    mock_saunum_client,
+    side_effect: Exception,
+    error_base: str,
+    mock_setup_entry: AsyncMock,
+) -> None:
+    """Test reconfigure flow error handling."""
+    mock_config_entry.add_to_hass(hass)
+    mock_saunum_client.connect.side_effect = side_effect
+
+    result = await mock_config_entry.start_reconfigure_flow(hass)
+
+    assert result["type"] is FlowResultType.FORM
+    assert result["step_id"] == "user"
+
+    result = await hass.config_entries.flow.async_configure(
+        result["flow_id"],
+        TEST_RECONFIGURE_INPUT,
+    )
+
+    assert result["type"] is FlowResultType.FORM
+    assert result["errors"] == {"base": error_base}
+
+    # Test recovery - clear the error and try again
+    mock_saunum_client.connect.side_effect = None
+
+    result = await hass.config_entries.flow.async_configure(
+        result["flow_id"],
+        TEST_RECONFIGURE_INPUT,
+    )
+
+    assert result["type"] is FlowResultType.ABORT
+    assert result["reason"] == "reconfigure_successful"
+    assert mock_config_entry.data == TEST_RECONFIGURE_INPUT
+
+
+@pytest.mark.usefixtures("mock_saunum_client")
+async def test_reconfigure_to_existing_host(
+    hass: HomeAssistant, mock_config_entry: MockConfigEntry, mock_setup_entry: AsyncMock
+) -> None:
+    """Test reconfigure flow aborts when changing to a host used by another entry."""
+    mock_config_entry.add_to_hass(hass)
+
+    # Create a second entry with a different host
+    second_entry = MockConfigEntry(
+        domain=DOMAIN,
+        data=TEST_RECONFIGURE_INPUT,
+        title="Saunum 2",
+    )
+    second_entry.add_to_hass(hass)
+
+    result = await mock_config_entry.start_reconfigure_flow(hass)
+
+    # Try to reconfigure first entry to use the same host as second entry
+    result = await hass.config_entries.flow.async_configure(
+        result["flow_id"],
+        TEST_RECONFIGURE_INPUT,  # Same host as second_entry
+    )
+
+    assert result["type"] is FlowResultType.ABORT
+    assert result["reason"] == "already_configured"
+
+    # Verify the original entry was not changed
+    assert mock_config_entry.data == TEST_USER_INPUT