Police have confirmed that the discovery was made at Blackbridge Brook in Havenstreet yesterday (Sunday).
Joyce went missing from Green Street in Ryde on Tuesday night and was last seen at 23:50. An appeal for information on her whereabouts was launched on Friday afternoon.
Volunteers from WightSAR and HampshireSAR have spent the weekend searching the Ryde area, later turning attentions to Whippingham.
Hampshire Constabulary day they are waiting for formal ID, but family members have been informed.
The death is not being treated as suspicious and a file is being prepared for the coroner.