TUNNEL ABSEILING PLUS tour the underground

A wartime fortress makes a fine adventure playground. This 150-minute tour takes you into the 550-meter San Giovanni underground fortress, where you learn basic abseiling, descend natural rock, and walk through concrete chambers shaped by both construction and nature. I like the way it mixes a real historical site with a hands-on activity, rather than treating the fortress as just another place to look at.

I especially like the small group of up to eight, which gives instructors room to explain the ropes and watch each person closely. The final wine tasting and audio-visual presentation also give the outing a sociable finish. The main consideration is simple: you need warm clothes and sturdy shoes with non-slip soles, and the underground temperature stays around 14 to 16°C.

Key points to know before you book

• 550 meters of wartime underground space: San Giovanni is an unfinished World War II fortress, with high concrete rooms, natural rock, and two underground levels.
• Beginner-friendly abseiling: You receive a technique briefing, equipment instruction, a practice session, and a demonstration before descending.
• Abseil Plus adds a third descent: The extra cascade-rock descent is uneven and slippery, making it the more demanding choice.
• Small groups keep the instruction personal: No more than eight people join the English-language tour.
• Bring the right shoes: Hiking shoes or sturdy sports shoes with non-slip soles are mandatory.
• A curious finish: After the audio-visual presentation and wine, the bravest participants can switch off their head torches and find the exit in complete darkness.

Why this Zagreb County adventure is different

Many underground tours ask you to walk quietly and look at old walls. This one asks you to put on a harness and move through the site under your own control. That changes the mood. You are not just hearing about the fortress. You are paying attention to the rock, the rope, the height, and the space around you.

San Giovanni is a 550-meter-long World War II fortress that was left unfinished. Its incomplete state is part of its appeal. Concrete construction meets exposed natural rock, creating a place that feels less polished than a restored museum and more like an abandoned military project brought back into use.

The site was forgotten and hidden until recent years, when it was cleared, repaired, and prepared for visitors. That gives the tour a sense of discovery without requiring you to go far from the established route or find your own way through an unsafe ruin.

At $88 per person, this is not a low-cost underground walk. But the price includes the fortress entrance, certified abseiling equipment, professional instructors, insurance, special effects, transport back to the starting point, and wine tasting. I see it as a good value for someone who wants a full activity rather than a short photo stop.

The first 20 minutes: equipment, technique, and nerves

The tour begins with an introduction to abseiling and an explanation of the equipment. The instructors show you how the system works, then let you practise on a horizontal surface before anyone goes over the edge.

That order matters. If you have never abseiled, the rope, harness, and descent device can seem like a lot to take in. A ground-level exercise lets you focus on the basic movements before height becomes part of the equation.

You also watch a demonstration. This is useful for visual learners, and it gives you a clear idea of body position and rope control. The instructors provide all equipment, and it is certified to current standards and checked regularly.

You do not need previous experience. The instructors provide professional support and backup throughout the descents. Just as important, you can decide on the spot which descent feels right for you. The tour is designed to build confidence gradually, not pressure you into the hardest option.

The atmosphere should suit someone who feels excited but slightly nervous. The guides Sara and Marko have been praised for explaining things clearly and creating a friendly, reassuring mood. Patience is valuable here. Good abseiling instruction is not about rushing you down. It is about helping you understand what you are doing.

The first descent: a gentle introduction to the rock

After the briefing, you put on your equipment and descend the vertical natural rock. The easier version involves walking down the rock face while supported by the rope.

This is the right choice if you want to try abseiling without adding a jump. You still experience the height and the unusual feeling of moving down a rock face, but your feet remain connected to the surface. The instructors back you up, so you can concentrate on the technique instead of trying to remember every instruction at once.

You can repeat the descent in a slightly harder version that includes a vertical jump. That option adds a quick burst of adrenaline, but it remains suitable for beginners under instructor support.

I like this two-step format. It gives you a practical way to judge your comfort level. Someone who arrives imagining a bold descent may decide the walking version is plenty. Someone who gets the hang of the rope quickly can try the jump.

The experience is not a free-for-all. The available descent choices depend on what you feel comfortable attempting, and you make that decision during the tour. This is especially helpful in a small group, where the guides can pay attention to individual reactions.

Entering the high concrete chambers

Once you leave the rock descent, you enter the fortress itself. The underground rooms are built in concrete and rise higher than you might expect from an enclosed military structure.

The transition from natural rock to unfinished concrete is one of the most interesting parts of the route. The fortress does not look like a single, tidy architectural style. It is a combination of human construction and the surrounding rock, with the unfinished sections adding to the sense of time stopped halfway through a project.

The walk is accompanied by special effects. These include audio-visual elements and a projection that help set the mood and connect the space with its past. This is not the same as a long museum lecture, so the historical content comes through the setting, the guide’s explanation, and the presentation.

You should expect an atmospheric visit rather than a detailed military archive. If your main interest is technical World War II fortification design, the information may feel limited. If you want to understand how an old underground site can feel eerie, physical, and memorable, the combination works well.

The building has two levels. That layout gives the Abseil Plus option its extra challenge and makes the route feel like more than a straight passage through one tunnel.

Abseil Plus and the slippery cascade rock

Abseil Plus includes the first two descent options and adds another descent on cascading rock inside the fortress. This is the point where the activity becomes more demanding.

The rock is described as uneven and slippery, so your footwear matters here. Non-slip soles are not a minor suggestion. They are mandatory, and the agency can adjust or refuse participation if your footwear is inadequate.

The extra descent works well as a progression. You have already had a chance to practise the technique on the easier sections, so you approach the cascade rock with a better feel for the equipment and your balance. Even so, this is not the version I would choose automatically if you dislike slippery surfaces, enclosed spaces, or uncertain footing.

Abseil Plus also allows you to try a simultaneous descent in pairs. That adds a social element and may appeal to friends or couples who want to share the challenge. The supplied information does not specify that every pair will descend together, so treat it as an available option rather than a guaranteed part of every run.

If you prefer a milder outing, the standard Abseil tour still includes the underground fortress and beginner-friendly descents. You do not need to choose the hardest package to get a worthwhile experience.

History, sound, and the walk through darkness

The fortress is more than a backdrop for an outdoor sport. It was built during World War II but left unfinished, then remained out of public view for years. Walking through it gives the historical material a physical scale that a photograph cannot provide.

The audio-visual presentation near the end adds another layer. It is designed to take you back in time, and it gives the tour a pause after the physical activity. I appreciate that balance. You get movement and adrenaline first, then time to absorb the place.

The final challenge is optional. Participants who feel brave can turn off their head torches and find their way out in pitch darkness. This sounds simple until you remember that darkness changes your sense of direction quickly, especially underground.

You should skip this part if it would cause distress. The tour is already complete without it. It is a playful ending for people who enjoy a controlled scare, not a test you need to pass.

The tour is not recommended for people with claustrophobia or epilepsy. Children under 10 cannot participate. These limits make sense given the enclosed setting, head torches, special effects, and abseiling equipment.

The practical comfort details that matter

The underground temperature is around 14 to 16°C. Bring a warmer layer, even if the weather outside is hot. A light jacket or warm sports top will make the walking and waiting periods much more comfortable.

Wear hiking shoes or sturdy sports shoes with non-slip soles. Open footwear, smooth soles, or casual shoes that do not grip well are not suitable. The agency can change the tour if a participant arrives with inadequate footwear.

The outing lasts about 150 minutes, which is long enough to feel substantial without taking an entire day. The tour is conducted in English, and the group is limited to eight participants. That small number is useful during the equipment briefing and the individual descent choices.

At the end, an air-conditioned van takes you back to the starting point. The tour then closes with conversation and a glass of wine. This final social moment helps the outing feel like a complete local experience rather than a climb followed by a quick goodbye.

Alcohol and abseiling do not mix. The agency can adjust the tour if visitors are under the influence of alcohol or drugs. Save the wine tasting for the end, as intended.

Weather can also affect the plan. The agency reserves the right to change or adjust the tour in poor conditions. That is a reasonable safety measure, especially when the route includes rock and transport between parts of the experience.

Who will get the most from the $88 price

I would recommend this to you if you want three things in one outing: a historical site, a physical challenge, and a small-group social experience. It works particularly well for friends who want something more active than a standard city tour.

The tour also suits cautious beginners. You do not need previous abseiling experience, and the descent choices let you set your own level. The guides have earned praise for clear explanations, friendly support, and making first-timers feel safe.

The price is easier to justify if you plan to take part in the abseiling rather than simply watch. You receive equipment, instruction, entrance, insurance, effects, transport back, and wine. For a two-and-a-half-hour activity with certified guides, that package is fair, though still a splurge for budget visitors.

I would be less enthusiastic if you mainly want a quiet history tour. The abseiling is not a small add-on. It shapes the whole experience. Likewise, someone uncomfortable with enclosed spaces may find the underground setting more stressful than enjoyable.

The strong 4.8 rating from 12 bookings fits the tour’s main strengths: friendly instruction, a sense of safety, historical content, and a memorable setting. One useful point from the feedback is that some people wished they could abseil more than once. If you already enjoy rope activities, the standard route may feel brief, and Abseil Plus will probably suit you better.

Booking flexibility and choosing your version

You can cancel up to 24 hours before the activity for a full refund, and reserve now while paying later. Private tours and other dates or times are available on request through WhatsApp at +385 98 316 322.

Choose the standard Abseil tour if you want a first taste of the activity, prefer a gentler pace, or are unsure how you will react to height. Choose Abseil Plus if you want the extra cascade-rock descent and the option of a paired descent.

You can also make the final choice based on comfort during the tour. That flexibility is one of the better features here. A good adventure tour should leave room for courage and common sense to coexist.

Should you book the Tunnel Abseiling Plus tour?

Book it if you want an unusual half-day activity with real physical involvement and a clear beginner pathway. The combination of a forgotten World War II fortress, natural rock, concrete chambers, special effects, and a wine finish gives you more variety than a standard abseiling session.

Skip it if you have claustrophobia, epilepsy, are under 10, or do not have proper non-slip footwear. Also think twice if you want a purely historical visit or would rather avoid heights and slippery rock.

For most suitable participants, I see the Abseil Plus version as good value at $88. You get enough instruction to feel prepared, enough history to give the place meaning, and enough challenge to make the outing stick in your memory.

FAQ

How long does the Tunnel Abseiling Plus tour last?

The tour lasts 150 minutes, or about two and a half hours.

Where does the tour take place?

It takes place in Zagreb County, Croatia, at the underground World War II fortress San Giovanni.

How large is the group?

The tour is limited to eight participants.

Is the tour available in English?

Yes. The live tour guide language is English.

Do I need previous abseiling experience?

No. The tour is designed for beginners and includes instruction, equipment familiarization, a horizontal practice exercise, and a demonstration.

What shoes should I wear?

Wear hiking shoes or sturdy sports shoes with non-slip soles. Non-slip footwear is mandatory.

What should I wear underground?

Bring warmer clothing because the underground temperature is approximately 14 to 16°C.

Is the tour suitable for children and people with claustrophobia?

Children under 10 are not permitted. The tour is not recommended for people with claustrophobia or epilepsy.