K.P.
Wow! This is a great opportunity for your son to experience the beach.
We travel a lot with our little guy so I would suggest the following for the flight:
- TYLENOL! You have no way of knowing whether or not your little one is teething and a plane ride is no time to find out! I always give my munchkin a little dose (dr. recommended) before we fly just in case.
- Extra clothes and more diapers than you think you will need. Again, the change in pressure and atmosphere on the plane can do strange things to their bellies, not to mention time changes and different foods. I always make sure to have an extra outfit for him on the plane "just in case".
- Blanket for the baby in case it's chilly
- Plenty of books and little things to keep him entertained. I usually pick-up a few new things and save them for his cranky time on the plan. Somehow a new little toy takes the edge off for him!
- Check with your airline carrier regarding luggage alottment for the baby. Some allow the baby to have their own bag, carseat and stroller. Some charge. It's good to know ahead of time.
- Baby's documents in at least two places. I have a copy of the birth cert with me and one in my suitcase just in case!
As for what to do in Bali... take him everywhere! Let him splash in the water, play in the sand, explore the hotel room. Make sure he has plenty of sunblock and a hat. Bring a couple of sippy cups so he stays hydrated and make sure that you have access to some kind of grocery store so you can go and buy bottles of juice and milk rather than having to purchase in a restaurant or hotel lobby ($$$$).
Have a great time!