Things are looking up for Arinaga: It's tidied itself up in recent years and is now a great east coast spot to stop for lunch by the sea and a swim. While the town itself is residential the long promenade along the coast brings in the locals every weekend for seafood and sea air. Don't miss the giant fish and the excellent restaurant at the far north of the promenade.
Arinaga is often windy in the summer but normally sunny enough for a swim: Hop in by the jetty or at the little lido just to the north.
El Cabron, about two kilometres north of Arinaga through the dunes, is right among the island's top dive spots. Divers just walk in from the tiny beach and within metres are surrounded by shoals of grunts and big groupers. To dive El Cabron talk to dive shops in the resorts and in Las Palmas: It's on every good dive shop's list.