Trigg Island is the next beach north of Scarborough — not a real island, just a small rocky outcrop and a long stretch of sand named after it. It is one of the best surf beaches in metropolitan Perth, with a reliable left-hand break off the rocks. The Trigg Island Beach Cafe sits above the sand and is a local institution for breakfast.
The bushland behind the beach is part of Bold Park, with walking trails through coastal heath. A 25-minute walk along the coast path from Scarborough; on a good summer day you can plausibly do both beaches in an afternoon.