The obvious ones are - walking, birdwatching, fishing, golf, swimming at the local beaches, eating out, or visiting local churches and castles with which Gower is well endowed. Here's a selection of other things and/or more details.
Learn Digital Photography whilst being guided around Gower:
This page gives a flavour of the more obvious things to do in Gower and surrounding area, but it is not exhaustive. Have a good look on the visitSwanseabay websitre or the Visit Wales websites or on some of the links provided below.
As examples, of further afield, Pembertons Chocolate Factory, Folly Theme Farm, and Oakwood Park (quality) Theme park (similar to Chessington World of Adventures), are only a hour's drive away and are well worth visiting outside of Gower Peninsula itself.
Within Gower more close by you can do the following: Surfing, sea angling, Golf (6 golf courses in Gower), Birdwatching, Paragliding, Jet Skiing, Swimming, mountain biking, rock climbing, yachting, canooing, archery, horseriding/trekking, scuba and snorkelling, League Football and top flight Rugby Union are all available either in Gower or nearby Swansea and Mumbles.
Contact the following:-
Golf
There are five courses on Gower, and another close by. Pennard, Langland, Clyne, Gower, & Fairwood Golf Clubs are all in Gower (and Machynys Golf Club is close by at Trostre, near Llanelli). Gowerton houses a driving range.
Fishing
As seen in Sea Angler Magazine regularly, some of Wales very best Sea Angling (Bass, Plaice, Dab, Gurnard, Turbot, Whiting/Cod, Ray, Flounder, Mackerel, Tope and Golden Grey Mullet to name a few local species)Fishing tackle and bait at Country Angling at Gowerton, or Rogers Tackle at Swansea Marina - also Mainwarings in Sketty Cross, Swansea. The best venues are Mumbles Pier (for kids) and Crabbart, Fall Bay, Port Eynon point, Pennard Cliffs and Whiteford for Sea Bass, Mackerel and Tope.
Archery
Contact Perriswood Archery centre, Penmaen/Nicholaston, South Gower. It costs around £10 for a session.