There’s excellent snorkelling around the Wewak headland, over the outer reef and off the nearby islands (bring own gear).
Between mid-October and late April monsoon swells bring waves between 1m and 2.5m to PNG’s northern coast, and there are several good surf breaks around Wewak. Bring your own board.
You can organise tours to the Sepik, including some offered by Wewak-based operators.
Wewak's best accommodation is found in Wewak Town. Higher-end places include airport transfers in the price. There's also a cluster of lodgings opposite the airport, and a few options strung along the beautiful beach, served by frequent daytime PMVs; the latter tend to be rather isolated at night as there are no taxis.
The best dining options are confined to three Wewak Town hotels.
Few people come to the Sepik without buying at least one carving and buying just one is often a good strategy, as Sepik pieces are often heavy and large. Wewak is adequately supplied with supermarkets and pharmacies.