diff --git a/napalm_opnsense/opnsense.py b/napalm_opnsense/opnsense.py
index bf02d3a..aa105d3 100644
--- a/napalm_opnsense/opnsense.py
+++ b/napalm_opnsense/opnsense.py
@@ -1221,13 +1221,20 @@ class OPNsenseDriver(FirewallDriver):
         method's "never silently no-op on the thing the caller explicitly
         asked for" contract.
 
-        Lease removal is best-effort and non-fatal: the exact Kea
-        lease-delete endpoint shape is unverified in this codebase (unlike
-        reservations, ``get_dhcp_leases()`` only ever implemented the read
-        path) — a failure here just means a stale lease record lingers in
-        Kea until its own natural cleanup, which is cosmetic, not a
-        functional problem (a deleted reservation already prevents the
-        client from getting the same IP back).
+        Lease removal is best-effort and non-fatal — a failure here just
+        means a stale lease record lingers in Kea until its own natural
+        cleanup, which is cosmetic, not a functional problem (a deleted
+        reservation already prevents the client from getting the same IP
+        back). Endpoint verified live against a real OPNsense instance:
+        ``LeasesController`` is documented as "Abstract [non-callable]" with
+        a ``del_lease($ips=null)`` action
+        (https://docs.opnsense.org/development/api/core/kea.html) — the
+        concrete, callable route is the ``leases4`` controller (matching
+        ``search``, used above), and despite the ``$ips`` parameter name the
+        IP is passed as a URL path segment, not a JSON body field — a POST
+        body of ``{"ips": [ip]}`` (the natural reading of the signature)
+        returns ``{"status": "error", "message": "Missing lease IP
+        parameter"}``; only ``POST /api/kea/leases4/del_lease/{ip}`` works.
 
         :param mac: NIC MAC address of the reservation to remove.
         :param ip: IP address of the reservation/lease to remove.
@@ -1272,7 +1279,7 @@ class OPNsenseDriver(FirewallDriver):
             rows = leases.get("rows") or leases.get("leases") or []
             if any((row.get("address") or row.get("ip-address")) == ip for row in rows):
                 result["lease_found"] = True
-                del_lease = self._post("/api/kea/leases4/delLease", {"ip-address": ip})
+                del_lease = self._post(f"/api/kea/leases4/del_lease/{ip}")
                 result["lease_deleted"] = bool(
                     del_lease.get("result") == "deleted" or del_lease.get("status") == "ok"
                 )
diff --git a/tests/unit/test_driver.py b/tests/unit/test_driver.py
index fe40859..9addd9f 100644
--- a/tests/unit/test_driver.py
+++ b/tests/unit/test_driver.py
@@ -1379,8 +1379,14 @@ class TestDeleteDhcpReservationAndLease:
         reconfigure_call = driver.session.post.call_args_list[2]
         assert reconfigure_call.args[0] == "https://opnsense.example.com/api/kea/service/reconfigure"
         del_lease_call = driver.session.post.call_args_list[3]
-        assert del_lease_call.args[0] == "https://opnsense.example.com/api/kea/leases4/delLease"
-        assert del_lease_call.kwargs["json"] == {"ip-address": "172.22.8.253"}
+        # IP is a URL path segment, not a JSON body field — verified live
+        # against a real OPNsense instance; a {"ips": [ip]} body (the
+        # natural reading of the documented del_lease($ips=null) signature)
+        # returns {"status": "error", "message": "Missing lease IP parameter"}.
+        assert (
+            del_lease_call.args[0]
+            == "https://opnsense.example.com/api/kea/leases4/del_lease/172.22.8.253"
+        )
 
     def test_noop_when_no_reservation_and_no_lease_found(self, driver):
         driver.session.post.return_value = _make_json_response({"rows": []})