For the Galapagos:
For the daytime in the Galapagos, you will most likely want to be in shorts and a loose comfortable t-shirt or tank top. Consider bringing only one or two pairs of light pants to the Galapagos. They will be too warm usually, but you might want them for the plane and perhaps at night to enjoy the ocean nights. Also, bring a light sweater or sweatshirt so you won't miss magnificent nightly star-gazing.You must pass through Quito, which is also on the Equator, but high in the mountains with a cool climate. Arriving at the airport dressed for cold weather is wise, so pack a jacket, preferrably a waterproof one that can double as a raincoat in the islands.Footwear
Without a doubt, Teva-style sandals are the most useful footwear you can bring to the island. They can be worn during dry or wet landing on the islands, protect your feet from the hot, harsh volcanic landscape and keep them cool. You might want the protection and support of tennis shoes or sneakers, but we would recommend that you bring your older broken-in pair than a new pair that will suffer the damage of saltwater, volcanic rock, and sand.
A swimsuit or two is perfect for the water --the sun will dry them quickly and they are great for lounging around on the decks. If you have your own snorkeling equipment and you feel like bringing it with you, do so by all means. Often it is better to have your own equipment with which you are comfortable and certain of it fitting than renting from the boat or a shop. However, if you do not have your own, if your boat does not supply it, or you don't want to bring yours down, it is quite possible to rent from a shop in Quito. For those that like to spend hours snorkeling and diving deep, you might consider a shorty wet suit for the deeper 18-23 degree C waters.
Sunscreen We list sunscreen as its own section because its so important. The sun hits the equator hard and can burn you before you know it. We recommend SPF 45 waterproof sunscreen, and everywhere --don't forget the tops of your feet! Strong sunburn can be a debilitating condition-- especially for those with lighter skin.
Accessories Some other items that you might consider bringing are binoculars (7x25 are recommended), and extra camera batteries.
Money The official currency on mainland Ecuador and the Galapagos is the US Dollar. It would be wise to already bring some dollars in cash with you. You will want to have some cash on you to buy a t-shirt, a refreshing cola, etc. The airports in Quito and Guayaquil, as well as the mayor hotels have money exchange facilities. There is a bank in Puerto Ayora (a typical stop on your itinerary) that can change your traveler's checks, give cash advances on most credit cards, and ATM cardholders may be able to take out money. Carry your money, credit cards and the like in a money pouch (held close to your body).
Medication Always travel with all prescription medicines that you may need. Special medicines you should consider bringing along are motion sickness medication (if your sea legs don't develop quickly), and aloe-vera gel (in case you forget our advice about sunscreen), Quito is at 9,500 feet, (3,000m) and some people experience symptoms of altitude sickness which in most cases can be remedied by drinking lots of water, getting lots of rest (which can be difficult when travelling), taking aspirin, or if you experience symptoms of mild headaches, DIAMOX, a drug that increases oxygen profussion is readily available in Quito pharmacies. If you experience severe headaches or respiratory problems, consult a doctor immediately.