https://support.google.com/recaptcha/?hl=en#6175971
After the statement which details the supported screen readers, the documentation then details the audio challenge.
The visual challenge is not accessible when using VoiceOver on iOS 9.2 on an iPhone 5C as it is not possible to select the required images from within the challenge. The selection cursor is found around the set of images and when trying to select the appropriate image inside, a single image out of the set is the one image which is selected or de-selected.
Please can you confirm if the visual challenge should be accessible with VoiceOver?
Thanks,
Will