diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index 25a9b8518..00d2425a4 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -2836,7 +2836,11 @@ public:
         
         for (auto const& annotationTag: annotationTags)
         {
-            MGLAnnotationContext annotationContext = _annotationContextsByAnnotationTag[annotationTag];
+            if (!_annotationContextsByAnnotationTag.count(annotationTag))
+            {
+                continue;
+            }
+            MGLAnnotationContext annotationContext = _annotationContextsByAnnotationTag.at(annotationTag);
             [annotations addObject:annotationContext.annotation];
         }
         
@@ -2903,6 +2907,12 @@ public:
     {
         NSAssert([annotation conformsToProtocol:@protocol(MGLAnnotation)], @"annotation should conform to MGLAnnotation");
 
+        // adding the same annotation object twice is a no-op
+        if ([self.annotations containsObject:annotation])
+        {
+            continue;
+        }
+
         if ([annotation isKindOfClass:[MGLMultiPoint class]])
         {
             // The polyline or polygon knows how to style itself (with the map view’s help).
diff --git a/platform/macos/src/MGLMapView.mm b/platform/macos/src/MGLMapView.mm
index 4df365378..6679aaaa6 100644
--- a/platform/macos/src/MGLMapView.mm
+++ b/platform/macos/src/MGLMapView.mm
@@ -1635,7 +1635,11 @@ public:
         
         for (auto const& annotationTag: annotationTags)
         {
-            MGLAnnotationContext annotationContext = _annotationContextsByAnnotationTag[annotationTag];
+            if (!_annotationContextsByAnnotationTag.count(annotationTag))
+            {
+                continue;
+            }
+            MGLAnnotationContext annotationContext = _annotationContextsByAnnotationTag.at(annotationTag);
             [annotations addObject:annotationContext.annotation];
         }
         
@@ -1687,6 +1691,12 @@ public:
     for (id <MGLAnnotation> annotation in annotations) {
         NSAssert([annotation conformsToProtocol:@protocol(MGLAnnotation)], @"Annotation does not conform to MGLAnnotation");
 
+        // adding the same annotation object twice is a no-op
+        if ([self.annotations containsObject:annotation])
+        {
+            continue;
+        }
+
         if ([annotation isKindOfClass:[MGLMultiPoint class]]) {
             // The multipoint knows how to style itself (with the map view’s help).
             MGLMultiPoint *multiPoint = (MGLMultiPoint *)annotation;