With toddlers this young, you need calm water and zero logistical headaches. Aulani and Grand Wailea are the standouts here—both engineered specifically for the under-5 crowd with protected pools and beaches that won't terrify small kids. Aulani skews Disney (character moments, lighter crowds) while Grand Wailea goes full water-park mode across nine connected pools. Both cost serious money, but neither will have you white-knuckling a preschooler in rough surf. If budget's tight, Hilton Waikoloa trades some polish for Kohala Coast scenery and structured daily kids programming that actually frees up parent time.