Costa Rica is not all beaches and sand. It is a rain forest before anything else. So pick your foot ware wisely. When going to the beach, or hanging out at the pool in your hotel flip-flops are fine. Although you will see many locals always wearing flip-flops and they wear them where ever they go. But they are also used to it and grew up here. Many of the sidewalks are in very bad shape. Many are uneven, missing parts and having huge holes in them. In some areas, there are no sidewalks. Walking on gravel is not fun in flip-flops. I myself own two different pair of sandals. I have a pair of Teva’s which I absolutely love and a pair that is a little nicer for going out to eat. Teva’s have a very strong sole on them that is great for those small walks on uneven surfaces. But if you are going out hiking, I will suggest a good pair of hiking boots, even better if they are waterproof. Remember it’s a rain forest, it rains a lot. So, when you are out and about it could start raining at any moment. Open toed shoes and sandals are not a good thing when it starts raining. You need to protect your feet. Water does not drain quickly here from the streets and sidewalks, it can be a foot deep in places. Also, if hiking, most places will not let you wear any type of open toed shoe or sandal. This is to protect you from creatures that can come up and bite you in the foot. Snakes are a good example. Also, we have a lot of ants and many of them will bite. They do hurt also, I am allergic to them so I have to be extra careful when walking through the yard and grassy areas. So before you plan on wearing your flip-flops every where you go you need to think of where you will be going and what you will be doing. That will determine your foot ware.