Kai Iwi Beach, also known as Mowhanau Beach, is an accessible beach northwest of Castlecliff, Whanganui. It takes about 15 minutes to get there along Rapanui Road from Whanganui on State Highway 3. There is a small beach community, a nice reserve immediately before the main beach access, and a commercial campground. Go up to the top of Sunset Road for a great viewpoint.
The beach is bounded by streams and stunningly colourful eroding cliffs on either side. Note the warnings not to stand too close to the cliffs. To the southeast, the cliff runs all the way to Castlecliff; to the northeast, it runs to the next accessible beach at Ototoka.
From the reserve to the southeast, you will see yet another big pile of driftwood around the stream with a small sandy bay. Once the tide is out a bit, you can easily cross the bay and then the stream and go around the southeast point, with spectacular views down the coast and a couple of odd rock formations that have survived erosion so far.
You can also walk around the northwest side of the surf club building and immediately down to the beach. This would be the safest area to swim. Walk to the southwest, crossing the Kai Iwi Stream to arrive just below the impressive cliff outcrop. There is a bridge over the stream and a path back up the hill to the hamlet.
