I did this trip in September and it was outstanding. It's Playa Herradura and not Jaco. However, they have a van on the beach that takes you the short trip to Jaco for no additional charge.
I should add that the alternative, overland route to Montazuma is a bone shaker at the end because the road is not paved. Taking the boat is much faster and easier.
https://costaricaticas.com/explore-south ... aco-beach/The one caveat is that your feet will get a bit wet, getting on and off the boat. It's best to wear shorts and sandals that you can take off. The guides will carry your bags and secure and cover them on top of the boat, if necessary.
If it's a rainy day with rough seas, then it could make for an unpleasant trip. However, the rainy season is now finished on the Pacific coast, so the chances of that are very low until July or August of next year.
Zuma tours has a website for online booking. Definitely book in advance because they can fill up.