Zakynthos: Turtle Spotting, Marathonísi & Keri Caves Cruise

The best part of this Zakynthos turtle cruise is the chance to see Caretta caretta loggerhead turtles in Laganas Bay, then reach places that are awkward to visit from land. The turtles are wild, so sightings vary, but even one slow shape near the boat can make the trip worthwhile.

I like the clear swimming stops at Marathonisi Island and the Keri Caves, and I like the friendly crew, with Captain Dennis singled out for his good humor and steady handling. The price is also hard to fault at $25.41 per person. Just keep your expectations tidy: this is turtle spotting, not a guaranteed swim with turtles, and the boat’s glass bottom consists of several small viewing windows rather than a wide pane under your feet.

Key points to know before you book

• Loggerhead turtle spotting: Search the warm waters of Laganas Bay for Caretta caretta turtles in their natural setting.
• Three-hour coastal trip: Departures are listed at 9:00, 12:00, and 15:00, with return trips around 12:00, 15:00, and 18:00.
• Two main stops: Swim near Marathonisi, known as Turtle Island, and at the striking Keri Caves.
• Small glass viewing windows: The boat lets you look below the surface, but it is not a full glass-bottom floor.
• Agios Sostis departure: Meet near the Cameo Bridge, by the large yellow flags, and find the yellow Zante Sun boat marked Aquarium.
• Good low-cost value: The trip includes the boat and guide, but not food, drinks, or transport to the port.

What this Zakynthos cruise is really like

This is a short, sea-focused outing from the southern coast of Zakynthos. You board near Agios Sostis, close to Laganas Bay, and spend about three hours moving between turtle habitat, sea caves, and swimming water.

The appeal is simple. You get several different views of the coast in one morning or afternoon, without paying for a private boat. You also avoid spending the whole trip on open water because the route is broken into distinct parts: turtle spotting first, then caves and swimming.

The boat is described as spacious, safe, and certified with wildlife safety in mind. That matters here. Laganas Bay is an important nesting area for loggerhead turtles, so responsible boat handling is more important than getting as close as possible for a photograph.

The experience is rated 4.1 out of 5 from 694 ratings, which fits the nature of the trip. The strongest points are the views, pleasant crew, swimming stops, and price. The main sources of disappointment are the limited number of turtles, crowded swimming areas, and the modest size of the underwater viewing panels.

Finding the boat at Agios Sostis port

The meeting point can be easy to miss if you arrive in a hurry. Go to Agios Sostis port near the Cameo Bridge and look for large yellow flags. The boat is yellow, carries the Zante Sun logo, and is marked Aquarium, also written as ΑΚΟΥΑΡΙΟΥΜ.

Arrive 20 minutes before departure. That gives you time to find the correct boat, rather than trying to identify it from a line of similar vessels at the last minute.

There is no hotel pickup or drop-off. You need to make your own way to the port, and the activity ends back at the same place. Large bags and luggage are not allowed, so bring only what you need for a few hours on the water.

A passport or identity card is listed among the things to bring. You may not need to show it at every departure, but it is sensible to follow the stated requirement.

Turtle spotting in Laganas Bay

The trip begins with the part most people are waiting for: searching for Caretta caretta turtles. Laganas Bay is one of the Mediterranean areas where these large loggerheads come to feed and nest, and the boat keeps watch for them near the surface.

This is not a zoo visit. The crew cannot summon a turtle, and no departure can promise a particular number of sightings. Some outings have seen two turtles, while another has produced only one. That is normal for wildlife viewing, but it changes how you should judge the experience.

The best approach is to treat the turtles as a bonus within a coastal cruise, not as a guaranteed show. Keep your eyes on the water, listen for instructions from the crew, and have your camera ready without letting it take over the moment.

The boat’s viewing setup also deserves a clear explanation. It is called a glass-bottom vessel, but the underwater view comes through a few small windows in the bottom. One report found this less impressive than expected. You can look below the boat, but you should not picture a large aquarium-style floor.

Swimming with turtles is not assured, either. The description presents the chance to swim among loggerheads, but actual outings may involve turtle spotting from the boat only. One recorded experience saw a baby turtle hatch and reach the sea, which would be a remarkable sight, but it is not something you should expect on every trip.

Keri Caves and the first swim

After turtle spotting, the boat heads toward the Keri Caves. These are among the most memorable parts of the trip, with pale rock walls, clear water, and narrow openings shaped by the sea.

The boat may enter one of the caves, giving you a closer look at the rock formations and the reflected light on the water. The exact number of caves visited can vary. One outing entered a cave, while another passed through only one or two. The route is not a fixed cave-counting exercise.

Swimming at or near the caves is a major reason to bring a swimsuit. The water is described as clear and intensely blue, and you may be able to swim directly from the boat. That makes this stop feel more personal than simply looking at the caves from the deck.

The length of this stop can vary by departure and sea conditions. One account described a 20-minute swim at a nearby beach before continuing to Marathonisi. This is enough time for a quick swim and a look around, but not enough for a long beach visit.

If you are not comfortable in the water, the cave scenery still gives you something to enjoy. The swimming stops are a central part of the outing, though, so you will get more from the cruise if you are happy getting wet.

Marathonisi Island, the turtle-shaped stop

Marathonisi is known as Turtle Island because of its shape and its role as a nesting site for loggerhead turtles. The island’s Golden Beach is connected with turtle nesting, so the setting has ecological importance as well as visual appeal.

The stop usually gives you time to swim and rest on or near the beach. One account described about 50 minutes here, which is a useful amount of time for a swim, a break from the boat, and a few photographs.

The catch is crowding. Marathonisi is a popular stop for many boats, and its small beach can become busy. You may find the sand less peaceful than the island’s untouched reputation suggests. The water remains the stronger draw, especially if you want a final swim in a striking setting.

Treat the beach with care. This is a nesting area, and the reason for visiting is not just pretty sand. Follow crew instructions and respect any protected areas or wildlife rules given on the day.

The order of the stops may not be identical on every departure. A 9:00 trip has been described as visiting the caves before the longer Marathonisi swim, while other departures may use a slightly different sequence. The supplied schedule lists three daily start times, but conditions and boat operations can affect the precise flow.

Boat size, crew, and comfort

The boat is described as spacious and safe, and the experience is suitable for people who want a shared cruise rather than a private charter. Group size can make a real difference, though. One 15:00 outing had about 15 people, while larger boats nearby carried more than 30.

The 9:00 departure may be the best choice if you prefer a quieter start. One early outing had roughly 12 people on board, while the port was already much fuller by the time the boat returned. This is not a guarantee of group size, but it is a useful reason to choose the first sailing if your schedule allows.

The crew is one of the tour’s most praised features. Captain Dennis receives particular credit for making the trip enjoyable, and another highly rated outing featured a father-and-son captain team. The crew is described as friendly, helpful, accommodating, and good-humored.

That atmosphere matters on a short boat trip. A warm guide can explain what you are seeing, keep the mood relaxed, and help make up for a turtle sighting that is shorter than hoped. The guide is included in the price, though food and drinks are not.

Is $25.41 good value?

At $25.41 per person, this is a strong-value way to see several Zakynthos highlights in one outing. A private boat would give you more control over timing and stops, but it would cost more. This shared cruise keeps the price low while covering turtle habitat, Marathonisi, and the Keri Caves.

The value is best if you want variety. In three hours, you can see wildlife, coastal rock formations, and two different swimming settings. You also avoid arranging separate transport or boat hire for each place.

The price looks less attractive if your only goal is a long, quiet beach visit. Marathonisi can be crowded, and the swimming stop is shared with other boats. It is also not ideal if you expect a full glass-bottom viewing experience or guaranteed close turtle encounters.

Food and drinks are not included, so bring what you need within the boat’s rules. Large bags and luggage are not allowed. Pack light, with swimwear and only a small personal bag.

Free cancellation is available up to 24 hours before departure for a full refund. You can also reserve now and pay later, which helps if your Zakynthos plans depend on weather or changing schedules.

Which departure should you choose?

The 9:00 departure is the most appealing choice for people who prefer an earlier start and potentially smaller numbers. An early outing had about 12 people on board, and arriving back around noon meant seeing more people waiting for later trips.

The 12:00 sailing suits you if you want a midday break from sightseeing, though the bay and beaches may feel busier. The 15:00 departure gives you an afternoon on the water and returns around 18:00, making it useful for a relaxed evening afterward.

The exact crowd level is not guaranteed, and the route can change slightly. Still, the early boat is the practical pick if your priorities are space, calmer timing, and cooler conditions.

Who will enjoy this trip most?

I would recommend this cruise to families, couples, and first-time visitors who want an affordable introduction to Zakynthos from the water. It works especially well for anyone who wants both turtle spotting and swimming without committing to a full-day excursion.

You will enjoy it most if you can accept that nature sets the schedule. One turtle may be all you see, or you may be lucky enough to see more. The caves and swimming stops give the trip value even when the wildlife is shy.

This is less suitable for wheelchair users, as the activity is not accessible for them. It is also a poor fit if you need a quiet, private boat or a tightly controlled schedule. For that, a private charter would give you more freedom, though at a higher cost.

What to bring and what to expect

Bring your passport or ID card, swimwear, and a small amount of personal gear. A camera or phone is useful for the caves and coastline, but keep it secure around the water.

Do not bring pets, luggage, or large bags. There is no included food or drink service, so plan ahead within the operator’s rules.

Most importantly, bring patience. Turtle spotting depends on wild animals, and the sea can never be booked to a timetable. The crew can take you to the right area, but they cannot promise a perfect photograph or a swim beside a turtle.

Should you book the Zante Sun cruise?

Book it if you want a low-cost, three-hour taste of Zakynthos by sea, with a real chance of seeing loggerhead turtles and reliable access to the Keri Caves and Marathonisi. The crew, scenery, swimming, and price give it a lot going for it.

Choose the 9:00 departure if possible, especially if you prefer a smaller group. Just adjust your expectations about the glass bottom, turtle numbers, and beach crowds. This is a good shared boat trip, not a private wildlife expedition, and its value comes from the whole package rather than one guaranteed encounter.

FAQ

How long is the Zakynthos turtle cruise?

The cruise lasts three hours and ends back at the meeting point.

What time does the boat depart?

Departures are listed at 9:00, 12:00, and 15:00 each day. The corresponding return times are listed as approximately 12:00, 15:00, and 18:00.

Where do I meet the boat?

Meet at Agios Sostis port near the Cameo Bridge. Look for the large yellow flags and the yellow glass-bottom boat marked Zante Sun and Aquarium, also written as ΑΚΟΥΑΡΙΟΥΜ.

How early should I arrive?

You should arrive 20 minutes before your scheduled departure.

Is turtle spotting guaranteed?

No. The turtles are wild, so sightings vary. Some outings have seen one turtle, while others have seen two or more.

Can I swim with the turtles?

Swimming with turtles is not guaranteed. The cruise includes turtle spotting, but the actual experience may involve watching them from the boat only.

Does the boat have a full glass bottom?

No. The boat has several small viewing windows in the bottom rather than a large, fully transparent floor.

Are food and drinks included?

No. Food and drinks are not included in the activity.

Is hotel pickup included?

No. You must make your own way to Agios Sostis port, and the cruise returns to that same meeting point.

Can I cancel for a refund?

You can cancel up to 24 hours before departure for a full refund. A reserve-now, pay-later option is also available.

Is the cruise suitable for wheelchair users?

No. The activity is not suitable for wheelchair users.

What should I bring?

Bring a passport or identity card, along with swimwear and only a small personal bag. Pets, luggage, and large bags are not allowed.