diff --git a/desktop-widgets/command.cpp b/desktop-widgets/command.cpp
index adfd32960..fc7478f94 100644
--- a/desktop-widgets/command.cpp
+++ b/desktop-widgets/command.cpp
@@ -123,4 +123,9 @@ void mergeDiveSites(dive_site *ds, const QVector<dive_site *> &sites)
 	execute(new MergeDiveSites(ds, sites));
 }
 
+void purgeUnusedDiveSites()
+{
+	execute(new PurgeUnusedDiveSites);
+}
+
 } // namespace Command
diff --git a/desktop-widgets/command.h b/desktop-widgets/command.h
index 1bcc69089..134bb0147 100644
--- a/desktop-widgets/command.h
+++ b/desktop-widgets/command.h
@@ -49,6 +49,7 @@ void editDiveSiteLocation(dive_site *ds, location_t value);
 void editDiveSiteTaxonomy(dive_site *ds, taxonomy_data &value); // value is consumed (i.e. will be erased after call)!
 void addDiveSite(const QString &name);
 void mergeDiveSites(dive_site *ds, const QVector<dive_site *> &sites);
+void purgeUnusedDiveSites();
 
 } // namespace Command
 
diff --git a/desktop-widgets/command_divesite.cpp b/desktop-widgets/command_divesite.cpp
index a5dce00d1..3b35ddcc2 100644
--- a/desktop-widgets/command_divesite.cpp
+++ b/desktop-widgets/command_divesite.cpp
@@ -105,6 +105,31 @@ void DeleteDiveSites::undo()
 	sitesToRemove = std::move(addDiveSites(sitesToAdd));
 }
 
+PurgeUnusedDiveSites::PurgeUnusedDiveSites()
+{
+	setText(tr("purge unused dive sites"));
+	for (int i = 0; i < dive_site_table.nr; ++i) {
+		dive_site *ds = dive_site_table.dive_sites[i];
+		if (ds->dives.nr == 0)
+			sitesToRemove.push_back(ds);
+	}
+}
+
+bool PurgeUnusedDiveSites::workToBeDone()
+{
+	return !sitesToRemove.empty();
+}
+
+void PurgeUnusedDiveSites::redo()
+{
+	sitesToAdd = std::move(removeDiveSites(sitesToRemove));
+}
+
+void PurgeUnusedDiveSites::undo()
+{
+	sitesToRemove = std::move(addDiveSites(sitesToAdd));
+}
+
 // Helper function: swap C and Qt string
 static void swap(char *&c, QString &q)
 {
diff --git a/desktop-widgets/command_divesite.h b/desktop-widgets/command_divesite.h
index 58b3aabf5..9661bbffd 100644
--- a/desktop-widgets/command_divesite.h
+++ b/desktop-widgets/command_divesite.h
@@ -43,6 +43,21 @@ private:
 	std::vector<OwningDiveSitePtr> sitesToAdd;
 };
 
+class PurgeUnusedDiveSites : public Base {
+public:
+	PurgeUnusedDiveSites();
+private:
+	bool workToBeDone() override;
+	void undo() override;
+	void redo() override;
+
+	// For redo
+	std::vector<dive_site *> sitesToRemove;
+
+	// For undo
+	std::vector<OwningDiveSitePtr> sitesToAdd;
+};
+
 class EditDiveSiteName : public Base {
 public:
 	EditDiveSiteName(dive_site *ds, const QString &name);
diff --git a/desktop-widgets/tab-widgets/TabDiveSite.cpp b/desktop-widgets/tab-widgets/TabDiveSite.cpp
index f021f73dc..dc0b6be67 100644
--- a/desktop-widgets/tab-widgets/TabDiveSite.cpp
+++ b/desktop-widgets/tab-widgets/TabDiveSite.cpp
@@ -69,3 +69,8 @@ void TabDiveSite::diveSiteChanged(struct dive_site *ds, int field)
 	QModelIndex localIdx = model.mapFromSource(globalIdx);
 	ui.diveSites->view()->scrollTo(localIdx);
 }
+
+void TabDiveSite::on_purgeUnused_clicked()
+{
+	Command::purgeUnusedDiveSites();
+}
diff --git a/desktop-widgets/tab-widgets/TabDiveSite.h b/desktop-widgets/tab-widgets/TabDiveSite.h
index a31b1629d..b9c07ed69 100644
--- a/desktop-widgets/tab-widgets/TabDiveSite.h
+++ b/desktop-widgets/tab-widgets/TabDiveSite.h
@@ -16,6 +16,7 @@ private slots:
 	void add();
 	void diveSiteAdded(struct dive_site *, int idx);
 	void diveSiteChanged(struct dive_site *ds, int field);
+	void on_purgeUnused_clicked();
 private:
 	Ui::TabDiveSite ui;
 	DiveSiteSortedModel model;
diff --git a/desktop-widgets/tab-widgets/TabDiveSite.ui b/desktop-widgets/tab-widgets/TabDiveSite.ui
index 1d52555e3..b536f101a 100644
--- a/desktop-widgets/tab-widgets/TabDiveSite.ui
+++ b/desktop-widgets/tab-widgets/TabDiveSite.ui
@@ -14,6 +14,13 @@
    <string>Dive sites</string>
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <widget class="QToolButton" name="purgeUnused">
+     <property name="text">
+      <string>Purge unused dive sites</string>
+     </property>
+    </widget>
+   </item>
    <item>
     <widget class="TableView" name="diveSites" native="true"/>
    </item>