I found the following information on several stables on
experiencestmaarten.com:
"Horseback Riding:
Horses have been on the island since the 1600s and were among the only means of transportation for early residents. Today, as then, riding is an excellent way to experience St. Maarten/St. Martins secluded beaches and hillsides. Stables here have flourished in recent years, offering excellent facilities, daily rides, leasing and boarding.
Bayside Riding Club (Tel: 87 36 64), on the way to Le Galion Beach, features a daily beach ride and pony rides for children.
OK Coral (Tel: 87 40 72) at Coralita Beach offers a 2 1/2-hour beach ride.
Crazy Acres (Tel: 599/544-2793) offers lessons and boarding.
Lucky Stables (Tel: 599/544-5255) has horses for beginners and experienced riders, as well as expert guides who will take you on a one- or two-hour ride that features winding trails and a gallop in the Caribbean surf. Youll even find stables offering romantic night rides, with stops for champagne and toasted marshmallows on the beach."
I also found:
Caid and Isla: in Anse Marcel, phone: 590 87 45 70 (f)
The Crazy Acres Riding Center in Cole Bay has horses and ponies.
Rides cost about US$50 (Monday-Saturday 9 am-2 pm; phone 42793). [Recommended by the Travel Channel]
On Anguilla (6 miles from French St. Martin):
Cliffside Riding Center (Tel: 497-3667) in North Hill provides English- and Western-style riding for novices and experts alike.
Hopefully, one of the above will meet your needs.