Getting a peek into Zakynthos’ marine life and breathtaking coastlines is something many travelers dream about. This particular tour from Agios Sostis offers a chance to see the famous loggerhead turtles in their natural environment, explore the impressive Keri Caves, and enjoy some relaxing downtime on Marathonisi, also known as Turtle Island. Whether you’re traveling solo, with a partner, or as part of a small group, this trip promises a mix of adventure and tranquility, all packed into roughly three hours.
What makes this experience stand out? For us, it’s the opportunity to spot turtles in the wild—a true highlight for nature lovers—and the beautiful scenery that surrounds each stop. Plus, the boat’s glass bottom offers a glimpse into the underwater world without needing to dive in right away, which is perfect for those who prefer to stay dry but still want to see marine life. The only potential downside? The limited time on the island and in the caves might leave some wishing for more exploring or swimming opportunities.
This tour is a solid pick for anyone wanting a snapshot of Zakynthos’ natural beauty without an overwhelming time commitment. It’s especially suited for travelers who enjoy scenic boat rides, wildlife viewing, and a little beachside relaxation. Families with older children and anyone keen on memorable photos or a bit of snorkeling will likely find it a worthwhile addition to their itinerary.
Key Points

- Affordable Price: At around $28, this tour offers good value for a three-hour trip that includes multiple stops and wildlife spotting.
- Wildlife Encounters: The chance to see sea turtles in their habitat is a real perk, as confirmed by numerous positive reviews.
- Scenic Stops: The Keri Caves and Marathonisi are stunning locations, with dramatic limestone formations and lush greenery.
- Comfort and Convenience: The boat has both shaded seating and a sun deck, making it adaptable for different preferences.
- Limited Cave Swimming: You won’t be swimming inside the caves, which might disappoint some, but the stops near the cave zones still allow for swims in beautiful, clear waters.
- Flexible Booking: Free cancellation up to 24 hours in advance and the option to reserve now and pay later makes planning flexible.
The Experience in Detail

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Starting Point and Ease of Booking
The tour kicks off at Agios Sostis harbor, where you’ll look for the Nautilos flag. It’s straightforward to find, especially if you’re already exploring the Laganas area. The booking process is flexible—reserve your spot ahead of time without immediate payment, and cancel up to 24 hours before if your plans change. This flexibility is a real bonus, especially during uncertain travel times.
The Boat and Onboard Comfort
The boat itself is described as comfortable, with a choice between shaded seating and an open rear sundeck. We love this kind of setup because it caters to different comfort levels—whether you want to stay cool in the shade or soak up the sun with a good tan. The wind in your hair as the boat glides across the waters is part of the charm, making the trip feel relaxed and unhurried.
The Scenic Journey and Stops
As you set out, the views of Zakynthos’ coastline are striking. The boat navigates the protected waters of the National Marine park, a designated area for the preservation of the turtles and their habitat. Expect to see dramatic limestone cliffs and lush greenery along the way, which adds a layer of natural beauty to the trip.
One of the highlights is the stop at the Keri Caves. These caves are only accessible by boat, and the blue light that filters through limestone walls makes for some pretty incredible photos. You’ll have the chance to swim in the area—though swimming inside the caves isn’t permitted, the zones nearby offer the perfect spot for a refreshing dip. Reviewers mention the caves and the water’s clarity, emphasizing how stunning the scenery is.
More Great Tours NearbyMarathonisi: The Turtle Island
The star of the tour is undoubtedly Marathonisi, known locally as Turtle Island. It’s a tiny, protected spot where loggerhead turtles lay their eggs. The island itself is lush with pine, olive, and oak trees, offering a different kind of beauty compared to the caves. You get about an hour of free time here, which is enough to explore the small beach, take photos, or grab a snack from the bar.
Some reviews note that Marathonisi’s beach isn’t large and might be considered “mediocre,” but the real draw is the chance to see turtles in their natural habitat, which many travelers find unforgettable. Keep in mind that the beach is part of a protected area, so access is limited, and you can’t bring large luggage or heavy gear.
Food, Drinks, and Snorkeling
While food isn’t included, there are options available for purchase on Marathonisi—snacks, drinks, and ice cream. The reviews suggest that the bar’s offerings are tasty and provide a nice refreshment after swimming and exploring. If you plan to snorkel, bring your gear along, as the waters near the caves and the island are clear and inviting.
The Return and Overall Atmosphere
The ride back tends to be smooth and relaxed, with some reviewers mentioning slight delays but appreciating the captain’s friendly attitude and effort to accommodate everyone. The overall vibe is casual and fun, with the boat crew generally praised for their friendliness and knowledge.
What the Reviews Say

Readers consistently praise the guides and captains for their friendliness and knowledge, making the experience more engaging. Naomi highlights how incredible it was to see turtles in their natural habitat, while Santiago says the guide made the trip “very fun.” Babs enjoyed the combination of snorkeling, caves, and island time, describing it as an “amazing day trip.”
Many reviewers appreciate the scenery, with comments about the “beautiful caves and sea,” and the photo opportunities. Rachel notes the boat is roomy enough, and Nadia calls it the “best experience ever” thanks to the guide’s friendliness.
A few minor criticisms include the short amount of time on the island and in the caves, with some wishing for longer or more swimming options. Others mention that Marathonisi’s beach can be unimpressive compared to the overall natural beauty of the tour.
Price vs. Value

At around $28 per person, this tour offers a lot for the money. You get a scenic boat ride, a chance to spot turtles, and visits to iconic locations like the Keri Caves and Marathonisi. The inclusion of glassy-bottom views adds a fun element without extra cost, and the stops for swimming make it interactive. Considering the number of reviews with high praise, many travelers find this tour well worth the price.
Who Is This Tour Best For?

This experience is well-suited for nature lovers and wildlife enthusiasts eager to see the gentle loggerhead turtles in the wild. It’s also ideal if you want a short but memorable boat trip that combines scenic views with the chance for some swimming and photography. Families with older children who can swim and enjoy boat rides will also get a lot out of it.
If you’re looking for an active, adventure-filled day, this might be on the shorter side, but for those wanting a relaxing, scenic tour with wildlife, it hits the mark. Keep in mind that the limited time on the island and no swimming inside caves might be downsides for more adventurous travelers.
FAQs

- How long is the tour?
It lasts about 3 hours, which is enough to enjoy the main stops without feeling rushed. - Where does the tour start?
From Agios Sostis harbor, look for the Nautilos flag in front of the boat. - Is food included?
No, but snacks and drinks are available for purchase on Marathonisi. - Can I swim inside the caves?
No, swimming inside the caves isn’t permitted, but you can swim near the caves in designated zones. - What should I bring?
Sunglasses, sun hat, swimwear, towel, sunscreen, snorkeling gear, and some cash for snacks. - Is this tour suitable for families with children?
It’s best for older children who can swim and enjoy boat rides; the short duration and gentle nature make it manageable. - Do I need to book in advance?
Yes, it’s recommended to reserve beforehand, and cancellations are free up to 24 hours before departure.
Agios Sostis: Marathonissi, Keri Caves, and Turtle Spotting
“To see turtles in their natural habitat was incredible. Dramatic scenery and the sea was delightful.”
Final Thoughts

If you’re after a budget-friendly, scenic boat trip that offers the chance to spot sea turtles and explore some of Zakynthos’ most iconic sights, this tour from Agios Sostis is a solid choice. The combination of caves, island scenery, and marine life makes it a well-rounded experience that many travelers rave about.
While the short time on the island and no cave swimming might disappoint some, the overall value and the chance to see turtles in the wild are what make this tour stand out. It’s an ideal pick if you want a relaxed, picturesque outing that captures the essence of Zakynthos’ natural wonders.
This tour balances affordability, scenic beauty, and wildlife encounters—perfect for travelers looking to tick off some of Zakynthos’ most famous sights without a long day trip.
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