Should I bring a life jacket for my toddler?

No. They take up too much room. Rent them at your resort or beach club; most reputable operators provide them for free.

How do I deal with wet swimsuits on the return trip?

Pack a dedicated silicone or heavy-duty plastic 'wet bag' to keep damp items away from dry clothes.

Is it better to pack diapers or buy them there?

Bring enough for the flight and the first 24 hours, then buy a local pack at a supermarket. It saves immense space in your luggage.

Packing for a Family Tropical Vacation Without the Overpack

Stick to lightweight, moisture-wicking fabrics and pack one outfit per day plus two extras for accidents. Use packing cubes to separate family members' clothing and limit footwear to three pairs per person.

Categorize by person. Assign each family member a specific color of packing cube. This allows you to pull out a single cube for a child without dumping an entire suitcase on a hotel floor.
Apply the 1-2-3 rule for clothes. Pack 1 pair of shoes (worn on plane), 2 swimsuits, and 3 sets of shorts/tops. Anything more is usually dead weight that stays in the suitcase.
Consolidate liquids. Put all sunscreens, bug sprays, and shampoos in a single leak-proof toiletry bag. Use solid sunscreen sticks for kids to avoid liquid limit hassles and spills.
Optimize the carry-on. Pack one full change of clothes and all essential medications for every family member in your carry-on. If checked bags are delayed, you can survive for 24 hours.

Should I bring a life jacket for my toddler?: No. They take up too much room. Rent them at your resort or beach club; most reputable operators provide them for free.
How do I deal with wet swimsuits on the return trip?: Pack a dedicated silicone or heavy-duty plastic 'wet bag' to keep damp items away from dry clothes.
Is it better to pack diapers or buy them there?: Bring enough for the flight and the first 24 hours, then buy a local pack at a supermarket. It saves immense space in your luggage.