I'd like to know more. I didn't see this on the
DCL excursions, where/who/how much? Age limits? How long?

CH10Dad Glad you are interested! The more the merrier!
Just so everyone is clear this is not a DCL sponsored excursion. Other cruise lines do sponsor this one and it is open to anyone. Also be advised that it goes to the French side Orient Beach where they do not have tan lines if you know what I mean.
Here is the info about the excursion which is available at stmaartencruiseexcursions dotcom:
Fellow DISers,
For those of you interested in the ATV/Orient Beach Excursion I received a very prompt reply regarding questions I had about the excursion. I have attached portions of the email below, omitting email addys which are in violation of DIS, but if you would like a copy of the complete email with all addy's please pm me with your personal email address and I will be happy to forward you the entire email.
In a nutshell:1 1/2 hours of riding with 1 hour beach break.
Pick up is at 8:40am at port, drop off 11:40am at port
Tour is in groups of 10(ten) ATV's.
30% downpayment due at sign up and remainder due in cash or travelor's checks at time of excursion.
Let me know if you are interested so we can get one or two groups together!!!!
Greetings from St. Maarten,
We show current availability on the ATV Island Tour & Orient Beach tour on your arrival date. We take groups of ten riders.
The ATV Island Tour & Orient Beach Tour provides an exciting guided tour via ATV sports quadbikes around the French Side of St Maarten.
Its an absolutely unique way to "sightsee" and tour the island in the fresh air and outside the confines of buses and vans. The 2.5hr tour travels by public road for around 50% of the trip and on "Offroad" dirt tracks and beach for the other 50% of the excursion.
After being picked up at the cruise terminal, you will head to Point Blanch, for your safety briefing and departure. There is adequate storage under the seat for any bags or valuables.
The Quadbikes are all new, well maintained, and are "automatic", with no gears to worry about, so they are easy and safe for beginners. Helmets (provided free of charge) are compulsory. You will ride along palm lined public roads, off road dirt tracks, and sections of the beach.
There are a couple of stops for photo opportunities, and a highlight of this tour is the stunning panoramas of Orient Bay and Pinel Island on the French side of the Island. You will also enjoy great views of St. Barths, and the deserted Tintemare Island, which all provide great photo opportunities. The tour then heads down from the hills and onto Orient Beach, where you will spend an hour or so, at our Orient Beach club. There are bar, restaurant, shower, and toilet facilities. Swimming at Orient Bay is great, and a wonderful way to freshen up after your "dirtbiking". (Please note that free sunloungers are no longer available at this location but are available for rent on the beach). Then, its back onboard, for the return ride to Philipsburg.
Finally you will climb a steep mountain road way above the cruise terminal, where you can get great photos looking down on your cruise ship from high above the bay of Philipsburg.
Pickup Time at the cruise Ship Terminal is 8:40am / 11.40am (transfer time is under 10 mins).
The excursion is $69usd single riders, $55usd double riders, $33usd under 12yrs.
Riders must be 18yrs or older and we do not recommend the tour for under 7yrs.
Tour Specifications:
*
Transport is included in the cost of the excursion.
*
There is a combined 350lb weight limit per bike. Single and Double rider options are available.
*
The day consists of 2.5hrs Quadbiking and Beach Break.
*
Sunloungers, Drinks and Food are not provided on this excursion, but are available at extra cost at the Beach Club
*
You may opt to bring along your own snacks & drinks.
*
If you have additional questions not covered in this e-mail or not covered in our Website please contact our Live Help Dept. by visiting our Website Mon-Fri 9:00am to 5:00pm.
A 30% Deposit is required in order to secure your reservation (fully refunded in case of inclement weather cancellations or Ships not calling Port, please refer to our Terms of Reservation by visiting our website
The balance is due at time of excursion in cash or travelers check only.
Please remember that prices quoted on reservation requests or as show on our website at time of reservation request are not guaranteed until a reservation deposit is submitted for the excursion. To make sure you receive the quoted price please reserve the excursion within 24hrs of reservation request.
Please feel free to e-mail us or to contact our Live Help Dept. by visiting our Website. You may contact one of our live Operators for reservations as well as answers to any further questions before your confirmed reservation.
A confirmation e-mail will be sent to you with directions as well as additional relevant reservation instructions following your reservation submittal.
Please ensure to prebook your ATV adventure in order to avoid disappointment due to un-availability. This tour does sell out well in advance.