Hire a jeep for yourself for around $25 (1-4 people) or go individually at $5 pp. The dunes tour takes around 3 hours and leaves in the afternoon to make the most of the effect of the fading light on the sand formations. About 1km before Mui Ne town is the 'Fairy Stream', another 'tourist attraction'. In reality, it's a 15 minute walk upstream to a very small waterfall. Some tours include this, some don't.
A recent addition to Dune fun are quad bikes, they have a private area of dunes free from people hazards and are proving popular.
The city tours of Phan Thiet have a standard itinerary, taking in the Cham Tower, Phan Thiet market, the Dragon Garden and Takou mountain. The mountain, although not very high, may be of interest as it holds Vietnam's largest Buddha statue at 49m. If you're thinking of going it alone, the mountain is around 30km south of Phan Thiet. City tours cost around $16 pp, or $25 to hire your own personal jeep.
Other tours to outlying attractions can be arranged such as the Rock Garden (mudbath and massage center), the Kega Lighthouse, Binh Chau hot springs and also deep sea fishing. Check with your chosen travel agency for prices. The inland facing side of Nguyen Dinh Chieu is littered with tour and travel agencies, so organizing some out-of-town activities shouldn't be too taxing.

However, although easy enough to find instructors and book lessons for the aforementioned sport, it seems to be being left behind by the new craze -- kite surfing. During the 'windy' season, November to March, these kites with their attached riders below can be seen dotting the shoreline the entire length of the beach. Outside of these months the sport is still available, but the wind is unpredictable.
Learning the sport is accessible even for complete beginners. Many kite surfing schools have predictably sprung up, and competition is fierce between them. All the centres boast different kinds of courses and claim to be the best on the beach -- it's advisable to chat with the shop owners before making your decision to decide who you feel comfortable with. IKO (International Kiting Organization) is the PADI of the sport -- but there seems to be some confusion over who is IKO certified and who isn't. Certainly, you would want to choose a centre that has IKO certified instructors.

Boating :
Shades has the first trimaran in the area.  sailors may like to sample this exciting racing craft.
Other boats like catamarans, canoes and jet ski's can be rented.

Fishing :
Fishing is the areas main industry as one look at the evening horizon teeming with every variety of fishing craft from bamboo coracle to large trawler reveals.
Try some rock fishing, evening fishing or take a fishing tour.
All visitors should avail themselves of the abundant and reasonable shell fish, crayfish, prawns, squids and fish so fresh and perfectly prepared at the large variety of local and international restaurants here.

Golfing.
Novotel has a famous Golf facility in Phan Thiet just 20 minutes away plus Mui Ne has a Golf course of it own under construction, the first 8 holes will open very soon.

Tennis and Gymnasium facilities can be found here.

Pioneering.
There is an abundance of open space in this part of Vietnam, endless exciting vistas of coast and sea when you leave the built up areas. Its a wonderful place to explore the natural and local life.
50 miles offshore there is a little known volcanic Island that can be reached by daily ferry, clear water and fringing reef, visits must be arranged with local authorities first, but worth the effort for the adventurous spirit.