If you don't want to deal with much in the way of ice packs, these things keep well:
- PB&J sandwiches or wraps, turkey/cheese/cucumber matchsticks and spinach wraps
- string cheese
- pre-cut cheese cubes/slices and crackers
- veggies & hummus (carrots, cucumber slices, celery, green/red pepper slices all scoop up hummus well, cherry tomatoes are easy to eat in one bite).
- peanut butter in celery sticks.
- apples cut with 4 cuts so that it looks like a tic-tac-toe board from the top. The core will be in the center "square". Reassemble the apple and wrap or even just hold it back together with a rubber band, and it won't turn brown. You can also put peanut butter or any nut butter in place of the center core.
-grapes
-watermelon wedges
-orange wedges (provide juice and fiber). Kids are used to those because they serve them at the soccer games, track meets and so on.
- water in sturdy, reusable stainless steel (not plastic!) bottles. We either put ice cubes in it, or if we plan ahead, we freeze a few inches of water in it (about 1/4 to 1/3 of the way up). Then we top it off with cold water when we are ready to leave, and the bottles serve as ice packs we can then drink! They can also be refilled at the water fountains at the beach. You could also do this with juice, although we find the sugar makes everyone thirstier. You might mix some juice (frozen at the bottom and then top with plain seltzer if kids like something carbonated.
We don't take any chips/crackers in little snack bags, and we don't take sandwiches in ziploc bags - the bags end up all over the beach and the seagulls sometimes get them stuck on their beaks. We use plastic containers with lids (with several sandwiches in one, for example), and we stack the empties to come home or use a few for things like apple cores and orange peels. Some of the beaches we go to have ZERO trash cans, on purpose - they give you a plastic grocery bag when you pay the parking fee, and you have to take all your trash home with you. Keeps the beaches very clean, with no overflowing trash cans.