I only buy waterproof sandals for my kids. In the past I've worn saltwater sandals (too hard), sneakers (expensive) and striderite. They're cheap and hold up well. They are really waterproof and comfortable. My 2 year old can put them on and take them off (which some parents don't like) but it fits me. She has worn them everywhere and they hold up well.
Diadora Cattura Soccer Cleats Toddler Girls' Shoes for Athletic
56 Review
Saucony Girls Cohesion Running Little
52 Review
Breathable Fashion Sneakers for Baby & Toddler Boys & Girls: Bless Children Walking & Running Shoes
54 Review
Bloch Bunnyhop Leather Ballet Slipper Girls' Shoes for Athletic
57 Review
Felix Flora Toddler Flower Dress Shoes - Adorable and Comfy Flats
47 Review
Stylish and Comfortable pediped Flex Estella Mary Jane Shoes for Toddlers and Little Kids
60 Review
Adorable Blowfish Malibu Play-t for Toddler and Little Girls
47 Review
Flexible Comfort: pediped Flex Isabella Mary Jane for Toddlers and Little Kids
47 Review