Fish below. Castles above. Peace in between.

This Poseidon Submarine trip turns Rhodes Town’s waterfront into a two-screen experience: you glide around Mandraki Harbour and the Old Town above, then look down through huge windows at the life in the Aegean.

I love how short it is and how focused it feels—45 minutes that fit neatly into a busy day. I also love the big underwater payoff: you stay on the boat while the cabin sits below the surface, and you can watch a diver feed fish right in front of the windows. The one drawback to weigh: the lower viewing area can get tight and hot, so if you hate cramped spaces, plan your seating early.

Quick hits before you go

• 45 minutes on the water with a simple, easy route from Mandraki port back to the same meeting point
• 360° panoramic windows for underwater viewing while the vessel stays above sea level
• Diver feeding time with hundreds of multicolored fish right by your window (timing depends on your cruise slot)
• Harbour sightseeing loop that passes the Old Town walls, tourist harbour, and Elli beach, plus the area where the Colossus of Rhodes stood
• Air-conditioned cabin plus deck option, so you can choose between cool comfort and sea breeze

Entering the Mandraki Harbour scene from the Poseidon

Rhodes Town starts with the waterfront around Mandraki, and this cruise uses it like a front row seat. You board Poseidon Submarine at the dock area on Pl. Eleftherias 85100, at Mandraki port, on the Poseidon side opposite the Bank of Greece building. That’s a convenient start because Mandraki sits right in the middle of the action.

The vibe is practical: you’re not planning a whole day on the sea. You’re getting a focused ride with a built-in reason to look around—both at Rhodes above and the waterlife below. Even the time on the way helps. You’re not just going out and turning back; you’re passing recognizable spots while the clock stays friendly.

Getting comfortable: cabin air-conditioning vs deck breezes

One of the smartest parts of this experience is choice. You can stay inside the air-conditioned comfort cabin and watch through the large panoramic windows, or step out to the deck for open-air views of Rhodes from the water.

If you’re sensitive to heat, the cabin is a big plus. Some people also describe the lower area as sticky and warm, which makes the deck option more than a nice-to-have—it’s your reset button. If you want the best view of the underwater moment, aim to be downstairs in time when the diver enters the water, since that’s when the fish activity turns into the main event.

Also, keep an eye on where you sit. Reviews mention the lower deck can feel crowded and that people may take multiple seats at once. If your priority is space and a clear line to the windows, getting settled earlier helps.

The 45-minute route: Old Town walls and the Colossus area

This is a short cruise, so every stop is more like a highlight reel than a long sightseeing tour. You set off from Mandraki Harbour and then cruise past major Rhodes Town landmarks, with brief segments that keep the pace lively.

Here’s what you’ll see along the way in plain terms:

• You start at Mandraki Harbour and get a quick look at the port area from the water.
• You pass the area connected to the Palace of the Grand Master of the Knights of Rhodes, so you’re seeing the medieval core from an unusual angle.
• You also move by Old Town Rhodes, including the walls that define the city’s old defensive ring.
• You cruise by the tourist harbour and Elli beach, giving you a sense of how Rhodes Town mixes classic stone walls with modern waterfront life.

Why this matters for you: if you only have a few hours in Rhodes Town, this helps you “map” what you’re going to walk afterward. Seeing the Old Town walls and the harbour layout from the sea gives you instant orientation.

Underwater views: windows, 2.5 meters below, and the fish-feeding moment

The main draw is the underwater observatory effect. The vessel remains above sea level the whole time, while the underwater hull sits about 2.5 meters below the surface. That means you’re not doing an actual water-based activity yourself—you’re watching.

Then comes the part that most people remember: the diver feeding the fish. The timing is designed around your window view, so you’re meant to have your camera ready when the diver enters the water and starts feeding. The goal is a consistent, close-up viewing experience—hundreds of fish coming in near the windows, right where you can watch them without getting wet.

This is also why it works for families and mixed-age groups. A child can focus on movement and color. An adult can appreciate the ecosystem—fish behavior, how they gather, and how the seafloor looks through the glass. It’s not a museum diorama. It’s live activity, in a small time window you can actually fit into a vacation day.

When visibility gets cloudy: what to expect from the water

One thing to understand up front: underwater views depend on conditions. Some visitors note that visibility can be limited at times if the water gets cloudy. When that happens, fish may be harder to pick out, even if there are plenty around.

You can’t control water clarity, but you can control your expectations. Treat this like a short, guided viewing session, not a guarantee of Instagram-level clarity. When conditions are good, you’ll see lots of fish. When they’re not, you’ll still get the unique angle—Rhodes above you, underwater life below you—just with less sparkle.

Also, a few reviews mention that windows were not spotless at times. If you can, choose moments when the glass looks clear enough for you, and focus on movement near where the diver feeds. That feeding zone tends to create the most visual action.

Audio and explanations: what you’ll hear (and how to manage it)

The cruise includes an audio guide in English and German, plus there’s a live tour guide in English. That’s a nice mix because the audio helps you follow along when you’re looking outward, and the live guide can help connect the sights.

Practical note: some people report the commentary was hard to hear due to background music or the guide recording being too low. If you find yourself straining, step a bit closer to the speaker area when you’re on deck or pause your window-watching long enough to catch the key points. You’ll get more out of the history when you’re not trying to listen through wind and excitement.

In general, this isn’t a deep academic course. It’s history and context for the landmarks you can actually see from the boat—Old Town walls, the Knights of Rhodes area, and the harbour scene that shaped how the city functioned.

Value for money: why the $23 price often feels fair

At around $23 per person, this is one of the easier “yes” calls for Rhodes Town. The value is not only the submarine concept—it’s the combination: a short harbour loop with recognizable landmarks plus real underwater action with a diver feeding fish.

For many people, that mix is what makes it feel worth it:

• You’re paying for an unusual viewpoint, not just transport.
• You get a dedicated underwater moment built into the schedule.
• The total time is short enough that you’re not losing a big chunk of your day.

If you’re debating between a long boat trip and this, ask yourself what you want most. If your priority is a quick, memorable activity that keeps everyone engaged, this price-to-time ratio is strong. If you want hours of snorkeling or a full-day nature excursion, you’ll probably feel this is too brief—but it never pretends to be that.

Who this fits best in your Rhodes day plan

This works especially well for:

• Families with kids, because the viewing is easy and the fish-feeding moment is a clear payoff.
• Couples who want a low-effort activity with a scenic harbour loop and a unique underwater twist.
• Solo travelers who like short structured experiences that still feel fun and different.

It may not be ideal if:

• You hate tight spaces. The lower viewing area can feel crowded, and some people mention it gets hot and sticky.
• You’re expecting a guaranteed underwater “show” on every departure. One detail to watch: the 18:30 cruise doesn’t include the underwater show. If the diver feeding is your top reason for booking, pick a time that includes it.

Should you book Poseidon Submarine?

If you want a short, affordable activity that gives you both Rhodes Town views and a real underwater moment, I’d say yes. This is the kind of trip that helps you see the city from a new angle without eating your whole day.

Book it if you:

• Have 45 minutes to spare and want something that feels different from the usual walking route
• Want a family-friendly activity with a built-in underwater highlight
• Like the idea of 360° viewing without getting wet

Skip it or choose another option if:

• You’re booking specifically for the underwater show and your time slot is 18:30
• You’re very sensitive to crowded indoor spaces or heat on the lower deck

FAQ

FAQ

How long is the Rhodes Town submarine cruise?

The cruise lasts about 45 minutes.

Where do I meet the Poseidon Submarine?

Meet at Mandraki port at Poseidon Submarine, opposite the building of the Bank of Greece (Pl. Eleftherias 85100).

What languages are available on board?

You’ll have an audio guide in English and German, and there is also a live tour guide in English.

Is a bar available onboard?

Yes. A bar is available onboard, but drinks are not included.

Is the diver feeding and underwater show included on all departures?

The activity notes that the 18:30 cruise does not include the underwater diving show. For other times, the schedule includes the diver feeding the fish for underwater viewing.

Can I cancel for a full refund?

Yes. You can cancel up to 24 hours in advance for a full refund.