diff --git a/externs/olx.js b/externs/olx.js
index bb7b5d9075..dbfcb4af8f 100644
--- a/externs/olx.js
+++ b/externs/olx.js
@@ -4807,7 +4807,7 @@ olx.source.StaticVectorOptions.prototype.urls;
  *     maxZoom: (number|undefined),
  *     tileLoadFunction: (ol.TileLoadFunctionType|undefined),
  *     urls: (Array.<string>|undefined)}}
- * @api
+ * @api stable
  */
 olx.source.WMTSOptions;
 
diff --git a/src/ol/source/wmtssource.js b/src/ol/source/wmtssource.js
index ea9f2ece48..8907628e0f 100644
--- a/src/ol/source/wmtssource.js
+++ b/src/ol/source/wmtssource.js
@@ -34,7 +34,7 @@ ol.source.WMTSRequestEncoding = {
  * @constructor
  * @extends {ol.source.TileImage}
  * @param {olx.source.WMTSOptions} options WMTS options.
- * @api
+ * @api stable
  */
 ol.source.WMTS = function(options) {
 
@@ -196,7 +196,7 @@ goog.inherits(ol.source.WMTS, ol.source.TileImage);
  * "dimensions" option, and possibly updated using the updateDimensions
  * method.
  * @return {Object} Dimensions.
- * @api
+ * @api stable
  */
 ol.source.WMTS.prototype.getDimensions = function() {
   return this.dimensions_;
@@ -227,7 +227,7 @@ ol.source.WMTS.prototype.resetCoordKeyPrefix_ = function() {
 /**
  * Update the dimensions.
  * @param {Object} dimensions Dimensions.
- * @api
+ * @api stable
  */
 ol.source.WMTS.prototype.updateDimensions = function(dimensions) {
   goog.object.extend(this.dimensions_, dimensions);