Keri Caves Boat Trips: Which One Should You Book?

Shared boat trips start at $29 for a boat-only glass-bottom ticket from Agios Sostis and $32 for the three-hour speedboat or glass-bottom tours with hotel pickup. The four-hour route that adds Eros Cave and the Mizithres is $47. Private boats are priced per boat, not per person — from $276 for a skippered trip for two. Prices are the operators' live GetYourGuide figures and shift through the season.

Mostly from Agios Sostis, the small harbour at the western end of Laganas beach beside the Cameo Island bridge. Some boats leave from Laganas beach itself and a few from Limni Keriou, the harbour on the south-west coast closest to the caves. Most shared tours include hotel pickup from Laganas, Kalamaki and nearby resorts; boat-only tickets from Agios Sostis do not, so you make your own way to the quay.

The standard trip is three hours, including the turtle-spotting crossing of Laganas Bay, the caves and a swim stop at Marathonisi. The longer four-hour route adds the Mizithres rocks and Eros Cave. Half-day land-and-sea versions with an olive-press visit run four to five hours door to door. Private boats are typically three hours but can be extended.

On most trips, yes — every tour we list includes at least one swim stop in the caves area, and the speedboats and small boats sail through the arches themselves. The larger glass-bottom boats stop at the cave mouths. One boat-only ticket from Agios Sostis states in its own listing that the swim is in Oasi Bay in the caves zone rather than inside a cave. Check the stop list before you book if being inside the cave matters to you.

Speedboat if you want to pass through the arches and cover the most coast in three hours; glass-bottom boat if you want a calmer, drier ride, a floor to watch turtles through in the shallow bay, and an easier day with children or anyone prone to seasickness. The two most-reviewed trips on the coast are one of each, both $32 and both three hours, so the choice is about the ride rather than the price.

No, whatever a listing says. Loggerheads are in Laganas Bay through the summer nesting season and sightings on a morning crossing are common, but boats must keep 15 metres from a turtle and cannot chase or circle one, so it is the turtle's decision. Treat a sighting as likely, not promised, and pick your boat for the caves and the swimming rather than for a turtle guarantee.

Laganas Bay is the National Marine Park of Zakynthos, established in 1999 to protect loggerhead nesting beaches. Boats are limited to six knots inside the park, must keep at least 15 metres from turtles and limit observation to a few minutes, and are banned entirely from the highest-protection zone off the nesting beaches. On Marathonisi, access is daytime only, and umbrellas, anchoring and walking more than five metres from the shore are prohibited. See our Turtle Island guide for the detail.

No. The Blue Caves are at the northern tip of the island near Cape Skinari and are paired with Shipwreck Beach; the Keri Caves are at the southern tip and are paired with Marathonisi and turtle spotting. No boat trip does both. Our Blue Caves vs Keri Caves comparison explains which suits which kind of visitor.

Swimwear worn under your clothes, a towel, reef-safe sunscreen, a hat and water — nothing is served on most shared boats, though there are floating canteens at Marathonisi. Snorkel gear is rarely included on the shared trips, so bring your own mask if you have one. Several boats have no toilet on board; use the facilities at the harbour before departure.

Yes, more often than visitors expect. The caves face the open Ionian and the afternoon sea breeze builds swell along the south-west cliffs, so captains reroute or cancel for safety. Every trip we list offers free cancellation up to 24 hours ahead and reschedules or refunds weather cancellations. Book a morning departure early in your holiday so a cancelled trip can be rebooked.

For a couple it is closer in price than it looks: a skippered private trip for two is $276 for the boat, against $64 for two seats on a shared speedboat, and it buys you the departure time, the order of stops and as long in a cave as you like. For groups of four to six the per-head gap narrows further. Our private boat tours page compares skippered and self-drive options.

The three-hour glass-bottom boat from Agios Sostis — a wide, steady hull, a shaded deck, an hour at Marathonisi's beach and the glass floor for the turtle crossing. The four-hour glass-bottom route is the same boat type with more swimming. Avoid the speedboats with very young children or anyone who gets seasick; they are exhilarating in the arches and bouncy on the way back.