We went to TL 2 years ago when our youngest was 4 and NOT a very good swimmer. She wanted to bring her own swim vest but I told her NO as that is against the rules. Well...when we got there lots of people had brought in their own water wings, etc. The CMs were not telling them not to bring them in, however, they do have flotation devices there that you can rent/borrow. Do whatever is most comfortable for your child. We ended up not needing anything for her because she was mostly in the kiddy section. She was okay floating in the tubes in the lazy river and even the wave pool as long as DH or I were right next to her. Have a great trip...Lacee