diff --git a/okapi/core/OkapiServiceRunner.php b/okapi/core/OkapiServiceRunner.php
index a1d0abba..5433e5d9 100644
--- a/okapi/core/OkapiServiceRunner.php
+++ b/okapi/core/OkapiServiceRunner.php
@@ -39,6 +39,7 @@ class OkapiServiceRunner
         'services/caches/geocaches',
         'services/caches/mark',
         'services/caches/save_personal_notes',
+        'services/caches/save_user_coords',
         'services/caches/formatters/gpx',
         'services/caches/formatters/garmin',
         'services/caches/formatters/ggz',
diff --git a/okapi/services/caches/save_user_coords/WebService.php b/okapi/services/caches/save_user_coords/WebService.php
new file mode 100644
index 00000000..fa6ae917
--- /dev/null
+++ b/okapi/services/caches/save_user_coords/WebService.php
@@ -0,0 +1,105 @@
+<?php
+
+namespace okapi\services\caches\save_user_coords;
+
+use okapi\core\Db;
+use okapi\core\Exception\ParamMissing;
+use okapi\core\Exception\InvalidParam;
+use okapi\core\Okapi;
+use okapi\core\OkapiServiceRunner;
+use okapi\core\Request\OkapiInternalRequest;
+use okapi\core\Request\OkapiRequest;
+use okapi\Settings;
+
+class WebService
+{
+    public static function options()
+    {
+        return array(
+            'min_auth_level' => 3
+        );
+    }
+
+    public static function call(OkapiRequest $request)
+    {
+
+        $user_coords = $request->get_parameter('user_coords');
+        if ($user_coords == null)
+            throw new ParamMissing('user_coords');
+        $parts = explode('|', $user_coords);
+        if (count($parts) != 2)
+            throw new InvalidParam('user_coords', "Expecting 2 pipe-separated parts, got ".count($parts).".");
+        foreach ($parts as &$part_ref)
+        {
+            if (!preg_match("/^-?[0-9]+(\.?[0-9]*)$/", $part_ref))
+                throw new InvalidParam('user_coords', "'$part_ref' is not a valid float number.");
+            $part_ref = floatval($part_ref);
+        }
+        list($latitude, $longitude) = $parts;
+
+        # Verify cache_code
+
+        $cache_code = $request->get_parameter('cache_code');
+        if ($cache_code == null)
+            throw new ParamMissing('cache_code');
+        $geocache = OkapiServiceRunner::call(
+            'services/caches/geocache',
+            new OkapiInternalRequest($request->consumer, $request->token, array(
+                'cache_code' => $cache_code,
+                'fields' => 'my_notes|internal_id'
+            ))
+        );
+        $cache_id = $geocache['internal_id'];
+
+        self::update_notes($cache_id, $request->token->user_id, $latitude, $longitude);
+
+	$ret_value = 'ok';
+
+        $result = array(
+            'status' => $ret_value,
+            'user_coords' => $latitude.'|'.$longitude
+        );
+        return Okapi::formatted_response($request, $result);
+    }
+
+    private static function update_notes($cache_id, $user_id, $latitude, $longitude)
+    {
+        /* See:
+         *
+         * - https://github.com/OpencachingDeutschland/oc-server3/tree/development/htdocs/src/Oc/Libse/CacheNote
+         * - https://www.opencaching.de/okapi/devel/dbstruct
+         */
+
+        $rs = Db::query("
+            select max(id) as id
+            from coordinates
+            where
+                type = 2  -- personal note
+                and cache_id = '".Db::escape_string($cache_id)."'
+                and user_id = '".Db::escape_string($user_id)."'
+        ");
+        $id = null;
+        if($row = Db::fetch_assoc($rs)) {
+            $id = $row['id'];
+        }
+        if ($id == null) {
+            Db::query("
+                insert into coordinates (
+                    type, latitude, longitude, cache_id, user_id,
+                    description
+                ) values (
+                    2, $latitude, $longitude
+                )
+            ");
+        } else {
+            Db::query("
+                update coordinates
+                set latitude = '$latitude', longitude = '$longitude'
+                where
+                    id = '".Db::escape_string($id)."'
+                    and type = 2
+            ");
+        }
+    }
+
+}
diff --git a/okapi/services/caches/save_user_coords/docs.xml b/okapi/services/caches/save_user_coords/docs.xml
new file mode 100644
index 00000000..75b12c0f
--- /dev/null
+++ b/okapi/services/caches/save_user_coords/docs.xml
@@ -0,0 +1,25 @@
+<xml>
+    <brief>Update personal coordinates of a geocache</brief>
+    <issue-id>629</issue-id>
+    <desc>
+        <p>This method allows your users to to change the content of the user's
+        personal cache coordinates from one value to the other value.</p>
+
+        <p>Current personal coordinates for the geocache can be retrieved
+        using the <b>alt_wpts</b> field in the
+        <a href="%OKAPI:methodargref:services/caches/geocache#fields%">services/caches/geocache</a>
+        method.</p>
+    </desc>
+    <req name='cache_code'>
+        <p>Code of the geocache.</p>
+    </req>
+    <req name='user_coords'>
+        <p>The coordinates are defined by a string in the format "lat|lon"</p>
+	<p>Use positive numbers for latitudes in the northern hemisphere and longitudes
+	in the eastern hemisphere (and negative for southern and western hemispheres
+	accordingly). These are full degrees with a dot as a decimal point (ex. "48.7|15.89").</p>
+    </req>
+    <common-format-params/>
+    <returns>
+    </returns>
+</xml>