diff --git a/src/org/openstreetmap/josm/gui/preferences/server/OverpassServerPanel.java b/src/org/openstreetmap/josm/gui/preferences/server/OverpassServerPanel.java
index 682ab3552a5..f5867b97b3c 100644
--- a/src/org/openstreetmap/josm/gui/preferences/server/OverpassServerPanel.java
+++ b/src/org/openstreetmap/josm/gui/preferences/server/OverpassServerPanel.java
@@ -15,6 +15,7 @@
 import org.openstreetmap.josm.gui.widgets.HistoryComboBox;
 import org.openstreetmap.josm.io.OverpassDownloadReader;
 import org.openstreetmap.josm.tools.GBC;
+import org.openstreetmap.josm.tools.Utils;
 
 /**
  * Preferences related to Overpass API servers.
@@ -50,7 +51,16 @@ public final void initFromPreferences() {
      * Saves the current values to the preferences
      */
     public final void saveToPreferences() {
-        OverpassDownloadReader.OVERPASS_SERVER.put(overpassServer.getText());
+        // Get the new server -- add the trailing `/` if it does not exist to avoid duplicate entries.
+        // Other code locations assume that the URL has a trailing `/` as well.
+        String newServer = Utils.strip(overpassServer.getText());
+        if (!newServer.endsWith("/")) {
+            newServer += "/";
+        }
+        OverpassDownloadReader.OVERPASS_SERVER.put(newServer);
+        // Ensure that the new overpass server is added to history
+        overpassServer.setText(newServer);
+        overpassServer.addCurrentItemToHistory();
         overpassServer.getModel().prefs().save(OverpassDownloadReader.OVERPASS_SERVER_HISTORY);
         OverpassDownloadReader.FOR_MULTI_FETCH.put(forMultiFetch.isSelected());
     }
diff --git a/test/unit/org/openstreetmap/josm/gui/preferences/server/OverpassServerPanelTest.java b/test/unit/org/openstreetmap/josm/gui/preferences/server/OverpassServerPanelTest.java
new file mode 100644
index 00000000000..0c99e80918d
--- /dev/null
+++ b/test/unit/org/openstreetmap/josm/gui/preferences/server/OverpassServerPanelTest.java
@@ -0,0 +1,50 @@
+// License: GPL. For details, see LICENSE file.
+package org.openstreetmap.josm.gui.preferences.server;
+
+import static org.junit.jupiter.api.Assertions.assertAll;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.fail;
+
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+import org.openstreetmap.josm.gui.widgets.HistoryComboBox;
+import org.openstreetmap.josm.io.OverpassDownloadReader;
+import org.openstreetmap.josm.testutils.annotations.BasicPreferences;
+
+/**
+ * Test class for {@link OverpassServerPanel}
+ * @author Taylor Smock
+ * @since 18403
+ */
+@BasicPreferences
+class OverpassServerPanelTest {
+    /**
+     * Non-regression test for <a href="https://josm.openstreetmap.de/ticket/21953">#21953</a>
+     */
+    @ParameterizedTest
+    @ValueSource(strings = {"https://something.example.com/api", "https://something.example.com/api/"})
+    void testOverpassApiServerSaved(final String someRandomUrl) {
+        // We expect the API to have a trailing /
+        final String expected = someRandomUrl.endsWith("/") ? someRandomUrl : someRandomUrl + '/';
+        final OverpassServerPanel panel = new OverpassServerPanel();
+        panel.initFromPreferences();
+        final HistoryComboBox historyComboBox = Stream.of(panel.getComponents()).filter(HistoryComboBox.class::isInstance)
+                .map(HistoryComboBox.class::cast).findFirst().orElseGet(() -> fail("No HistoryComboBox found"));
+        assertEquals(OverpassDownloadReader.OVERPASS_SERVER.get(), historyComboBox.getText());
+        assertAll(OverpassDownloadReader.OVERPASS_SERVER_HISTORY.get().stream()
+                .map(server -> () -> assertNotNull(historyComboBox.getModel().find(server), "Server " + server + " not found")));
+        historyComboBox.setText(someRandomUrl);
+        panel.saveToPreferences();
+        panel.initFromPreferences();
+        assertEquals(OverpassDownloadReader.OVERPASS_SERVER.get(), historyComboBox.getText());
+        assertAll(OverpassDownloadReader.OVERPASS_SERVER_HISTORY.get().stream()
+                .map(server -> () -> assertNotNull(historyComboBox.getModel().find(server), "Server " + server + " not found")));
+        assertEquals(expected, OverpassDownloadReader.OVERPASS_SERVER.get());
+        assertTrue(OverpassDownloadReader.OVERPASS_SERVER_HISTORY.get().contains(expected),
+                String.join(";", OverpassDownloadReader.OVERPASS_SERVER_HISTORY.get()));
+    }
+}