You can visit the Galapagos any time of the year as there is always something wonderful happening in the Islands, especially with wildlife’s behavior and natural events.
From mid-June to early-December you have a mixture of warm and rain (afternoon showers), and Ocean waters are warmer and calmer due to the “El Niño” current. From mid-December to early-June is the cool/dry season on land and Ocean, especially because of the passing of the “Humboldt” current through the Archipelago.
In general, cruises include: accommodation in cabin with private facilities, guided excursions with professional Licensed bilingual guide, transfers within Galapagos (on cruise dates), Airport assistance, all meals on board while cruising, drinking water, tea, coffee.
Luxury and First class cruises also include usage of snorkeling equipment and most of them have sea-kayaks on board for guests. Some Luxury class cruises also include Wet suits and others and First class cruises have them available for rent on board.
Midrange and Economy class cruises have snorkeling equipment and Wet suits available for rent on board (in cash).
It depends especially on the level of comfort and facilities on board you are looking for:
On a general basis, unless included on the given price for the confirmed cruise, passenger needs to bring enough cash on board to cover costs like Galapagos entrance fee ($100 p.p. in cash on arrival to Islands), mandatory Transit Control Card ($20 p.p. paid before check-in in cash), snorkeling equipment & wet suit rental (in cash on board), personal expenses, extras, soft & alcoholic drinks, tips for guide& crew and other expenses not specified in the itinerary.
Some Luxury and First accept Credit Card payments on board for on board consumption but Midrange and Economy require payments in cash only. It is imperative that you bring enough cash (U.S. Dollars) in all cases to cover your expenses while cruising the Galapagos.