diff --git a/lib/dns/include/dns/zone.h b/lib/dns/include/dns/zone.h
index 86f2f36329..e30ac2f73f 100644
--- a/lib/dns/include/dns/zone.h
+++ b/lib/dns/include/dns/zone.h
@@ -1555,7 +1555,7 @@ dns_zone_getprimaryaddr(dns_zone_t *zone);
  */
 
 isc_time_t
-dns_zone_getxfrintime(const dns_zone_t *zone);
+dns_zone_getxfrintime(dns_zone_t *zone);
 /*%<
  * Get the start time of the zone's latest major step before an incoming zone
  * transfer is initiated. The time is set to the current time before the
diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index f1567be0ba..51eb23890a 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -18169,10 +18169,16 @@ dns_zone_getprimaryaddr(dns_zone_t *zone) {
 }
 
 isc_time_t
-dns_zone_getxfrintime(const dns_zone_t *zone) {
+dns_zone_getxfrintime(dns_zone_t *zone) {
+	isc_time_t xfrintime;
+
 	REQUIRE(DNS_ZONE_VALID(zone));
 
-	return (zone->xfrintime);
+	LOCK_ZONE(zone);
+	xfrintime = zone->xfrintime;
+	UNLOCK_ZONE(zone);
+
+	return (xfrintime);
 }
 
 static void