Mahurangi Regional Park sits at 192 Ngarewa Dr in Mahurangi East, Rodney, on the coast north of Auckland, and carries a 4.8 rating on Google.
The coastal parks of this region are working farms first and foremost: expect sheep and cattle grazing the paddocks, gates to shut behind you, and dogs often unwelcome, so check the rules before you set out. Facilities stay deliberately basic — long-drop toilets, picnic tables, no shop — so bring your own water and food. Beaches swim best around high tide, and small car parks fill quickly on fine summer weekends, so locals arrive early. When choosing a park, decide what the day is for: a lawn near the car suits young families, while a longer track rewards you with a quieter bay.
For a swimming-and-picnic day within easy reach of Auckland, Mahurangi Regional Park is worth the drive, and its 4.8 Google rating suggests plenty agree.