Ahoy there Kimberly, and welcome aboard planDisney!
I've spent a considerable amount of my time living and working at sea avidly picking out shore excursions to try out during my time off in various
Ports of Call across the globe, and something I really admire about the selection of
Port Adventures available on Disney Cruise Line is just how inclusive they can often be for folks and families comprised of different ages, sizes and abilities.
Taking a look at the offerings currently available to guests in
Progreso, it appears that you're considering between
Aké Ruins, Lazy River Tubing and Cave Swim (PGO38) or the
Mayapan Ruins, Lazy River Tubing and Cave Swim (PGO07). (Personally between the two of these, the Mayapan Ruins are the ones I prefer simply for how much more picturesque it is, with the added chance to climb up the Castillo de Kukulcán pyramid - something that is prohibited at Chichen Itza.) Otherwise, these two Port Adventures do end up at the same location for the aquatic-activity portions of the day.
I initially reached out to a Disney Cruise Line shoreside agent who confirmed that no weight limitations were posted online and could not find any on their end - these are typically explicitly stated for guest safety for activities like zip-lining or Port Adventures involving a helicopter. They did however encourage
speaking directly with the Port Adventures Crew Members on board for any additional insight they can provide.
I took the opportunity to dive in further with my research into the tour operators and found that the destination for the water activities - Cenotes Hacienda Mucuyché - does currently have a set of policies and restrictions of their own to be mindful of that include the mandatory use of a lifejacket and the ability to swim, including restrictions for those with "hypertension, epilepsy, heart disease, neck and/or back problems, recent surgeries" as well as a requirement for the guest to be ambulatory. In addition, access to these waterways and underground entry points are often via a series of steps that may not be accessible for those with difficulty walking, and the passageways can be narrow with limited visibility. The last time that I took part in a cave excursion in Mexico a few party members were unable to fit in a required lifejacket or physically take part in the water portion of the journey so keep in mind that the tour operators may use their discretion in deciding whether any activity is suitable or safe for participants, so it might also be worth reaching out to them directly about your situation to see whether they can confirm personally with you about whether they can accommodate your party member to avoid any disappointment.
I hope that this helps, Kimberly - here's hoping your group will be able to find a Port Adventure that works best for all of you on your upcoming voyage.
Come back to us here at planDisney for any other answers or advice as you prepare to set sail together!
We all deserve to enjoy adventures, wherever we are!
Prince