Mowhanau Beach is a beach at Kai Iwi, north of Whanganui, rated 4.8 on Google from 36 reviews. Reviews mention the barbecue area, picnics, the streams and the firm sand when the tide is out.
The website describes a river mouth beside dark sand and cliffs in bands of tan and rust, with a few baches, a boat ramp and dunes. Families visit most weekends, and the sandbars and channels at the river mouth change with the tides. The website also notes that conditions can be unpredictable at the river mouth, so check before swimming.
For families and picnickers in Kai Iwi who want a beach with streams, firm sand and a barbecue area, this coast north of Whanganui is a good day out.