If you are planning to swim, this is a day trip. However, if you are mostly walking around, then half day. It is a great morning to lunch outing.
The Strand has this wonderful long beach to walk on with Park Runs on some weekends. Small waves and warm water (which is rare in the Western Cape). Start at the Put Put side and work your way down to the pools. Parking is an issue here over weekends, make sure you are there early.
Jump from the Strand to Gordons Bay for rocks, books and food. We normally take a walk and swim. Then go to the second hand book store “Bikini Beach Books” on the way to Trawlers. If the take-away seems packed, it is for a good reason. Place your order and enjoy the view, it is worth it.