Hi, Alicia!
For your question, I went straight to the experts who not only have experienced various
Mexican Riviera Port Adventures but actually plan them for families with the tour operators -- they are the Disney Cruise Line (DCL) Port Adventures Team! Arny gave me a great list of suggestions for you and your family based on the ages of your children and by port of call:
Cabo San Lucas:
Cabo Dolphin Kids -- Ages 4 through 9
Cabo Dolphin Swim -- Ages 5 and up
Whale Watching & Deluxe Coastal Cruise -- All Ages
Puerto Vallarta:
Las Caletas Hideaway -- All Ages
Pirate Boat Sail & Snorkel Adventure -- All Ages
Sea Lion Encounter -- Ages 5 and up
My best advice as a mom of four is to consider how long you'll be in each port and plan your day based on the "majority rules" factor. You may decide that your resources are best spent on either splitting up the family or dividing the day into two smaller Port Adventures. Not everyone is going to be equally excited about every activity, and since your children are relatively small, you may consider leaving one or two on the ship to enjoy Disney's Oceaneer Club/Lab while the rest of you are on a Port Adventure. We like to take advantage of things we don't get to do on other vacations. I hope that helps give you an idea of what to expect and how to plan. Let me know what else I can do to help!
Have a wonderful day and a magical vacation. Bon voyage!
Andi