One of these towns in Riverton, which sits around Jacob's River Estuary. As a kid, my parents would often take us out here to swim at the beach and play on the famous Riverton rocks. The beach is safer than the Invercargill alternative, Oreti beach, as the sea is a bit calmer around this side of Southland. You can also swim with dolphins if you're lucky! It is about a 20 minute drive from Invercargill.
Riverton is fishing town, and is also one of New Zealand's oldest settlements. You can check out the local muesum, Te Hikoi Southern Journey, which has some interesting artefacts, and quite a bit about Southland Maori history. You can also drive 10 minutes to the stunning Colac Bay, which is a great surfing and swimming spot.
The best thing to do in Riverton is chill out with a book and a coffee, and admire the view. Or go swimming in summer! It's pretty damn cold in Winter. We're pretty close to Antartica don't you know...
The pub, the Aparima Tavern, has been done up and now makes the most of a stunning location overlooking the estuary. The menu is full of local seafood, so head down there for a beer and some bluecod. Or, head to the Beachhouse Cafe Bar for a coffee and some lunch.
If you want to experience the real 'wild South', Riverton is definitely worth a day trip.