Drake Bay has a dry and wet season, so it will depend on what part of the year it is. For hiking around, closed shoes are always recommended to increase safety during the activities in any season.
And for the beach and town, sandals are a good option. If you go on a tour on a boat, bring a long sleeves t-shirt, sunglasses, sunscreen, a cap, mosquito repellent, dry bag, poncho, enough water and a towel to make sure you have a good experience.
It is important when that when you take electronic devices with you that are not waterproof to bring a plastic bag or drybag to keep your equipment dry in case of rain.
Drake Bay is faraway from clinics and the doctor stays in town five days a week, and only for 8 hours eveday, so it is always smart to bring some medicine with you in case of any incident.
Being one step ahead I always very important, and mostly when you are about to visit a very isolated and remote place.