When I went down south, we stayed at Chandlers Smith Beach Villas for a week, just outside of yallingup. Much recommended, loved it there. 2 minute walk to the beach, not to mention you have plenty of places to go around you, such as Kato said above, Busselton, Dunsborough, Yallingup, Margaret River, Augusta... all within a short drive away (Augustas a little further). Not to mention Caves Rd which is full of caves to explore.

I had an awesome time down there.

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It's at the corner of get a map, and fuck off