This is the part of Marco's water that you drive yourself, and the island splits it neatly into two markets. On the Gulf side, concessions on the resort beach rent waverunners, paddleboards, kayaks, chairs and sailing dinghies by the hour, and run parasailing from the sand. On the river side, the marinas rent pontoons, deck boats and waverunners by the half or full day and put you straight into the Marco River with the Ten Thousand Islands in front of you. Which one you want comes down to a single question: do you plan to stay in sight of your towel?
Marco also has an unusually developed guided jet-ski market. Rather than an hour going in circles off the beach, several operators run led tours of two hours or more that push out through the passes and into the back bays, covering real distance. That is a genuinely better product than a rental lap, and it is the format most visitors here end up booking.
The rules are worth reading before the counter reads them to you, because on a personal watercraft you are the operator rather than a passenger and the responsibility is personal. Fourteen is the minimum age to operate a personal watercraft in Florida, no exceptions and no adult-supervision workaround. Most liveries will only rent to someone eighteen or over. If you were born from 1 January 1988 onward, running anything above ten horsepower requires Florida's Boating Safety Education Identification Card — or the temporary certificate a livery can issue once it has walked you through its safety briefing. Personal watercraft may not be operated between sunset and sunrise, which is why nobody sells a sunset jet-ski tour here. And every rider wears a flotation device and an engine cut-off lanyard.
The physical hazard on Marco is not the Gulf. It is the bottom. Behind the island and across much of the nearshore, water is two to four feet deep over hard sand, seagrass and oyster bar, and none of that is visible at speed on a bright day. Running out of the marked channels is how people break skegs, tear up seagrass beds and occasionally get hurt. Seagrass damage is a violation rather than an accident, and the back bays around Marco carry visible scarring from exactly this.
Then there are the slow zones. Manatee protection covers the Marco River, Collier Bay and Goodland Bay, and they are enforced. On a guided tour you spend the first fifteen or twenty minutes at idle before anybody opens the throttle, which surprises people who paid for an hour.