TUNNEL ABSEILING PLUS tour the underground

A 550-meter World War II fortress is the setting for this unusual Croatian adventure. You walk through unfinished military spaces shaped by both construction and nature, then use a rope to descend rock faces inside the underground complex. The final cascading-rock descent is the tour’s main challenge.

I like the gradual build-up: your first descents can be done with an instructor’s backup before you tackle the uneven rock. I also like the small maximum group of eight, the certified equipment, and the chance to try a paired descent. The main caution is simple: this is not a gentle cave walk. The rock may be slippery, the underground temperature is 14°C, and claustrophobia, epilepsy, poor footwear, or discomfort with heights can make it a bad fit.

Key points at a glance

• 550-meter underground fortress: Explore an unfinished World War II site where concrete construction and natural rock meet.
• Three-part abseiling challenge: Abseil Plus adds a more demanding descent down a cascading rock inside the fortress.
• Instructor-supported progression: Build confidence on the first descents before attempting the slippery section.
• Small groups of eight: The limited group size should allow closer attention from the certified guides.
• Wine tasting included: The active portion ends with a distinctly Croatian touch.
• Non-slip footwear is mandatory: Bring proper shoes, warm clothing, and a willingness to get close to uneven rock.

Inside the unfinished San Giovanni fortress

The appeal here is not just the rope work. You are entering the underground San Giovanni fortress, a 550-meter complex built during World War II but never completed. Its unfinished state gives the place a strange character. Human-made walls and military planning meet exposed rock and natural formations, so the site feels less polished than a standard museum and more like a place still revealing itself.

The fortress was forgotten and hidden until recent years. It has now been cleared, prepared for visitors, and fitted with audio-video effects and projections. Those additions give the underground visit some theatrical color, but the structure itself remains the main attraction. You get to see a military site where the work stopped before the final layer of order could be applied.

I value that combination because it gives the tour a clear sense of place. You are not simply being lowered into an artificial climbing space. You are moving through a former defensive site with a past, then using its rock and interior spaces for a modern adventure.

The guide leads the visit and explains the fortress and its history. One review specifically praised Ela, described as cheerful and friendly, and noted that she shared information about Rijeka and the cave. Guide assignments can vary, so you should not assume Ela will lead your date, but the experience is conducted in English and includes professional certified guides.

How the Abseil Plus route builds confidence

The Abseil Plus version is designed as a progression rather than one sudden test. The tour begins with the first two descents, where an instructor can provide backup. That matters if you have never abseiled before or if you need a few minutes to understand how your body, rope, and equipment work together.

Abseiling means descending a rock face with a rope. You control your movement with the supplied equipment while the guide helps you use the technique safely. This is active participation, not a ride where the operator does everything for you. You need to listen, follow instructions, and remain comfortable with the sensation of moving down a rock surface.

After the first descents, Abseil Plus adds the cascading rock inside the fortress. This section is described as more demanding because the surface is uneven and slippery. That makes the earlier practice valuable. By the time you reach this descent, you have had a chance to get a feel for the technique and gain a measure of security.

You can also try a simultaneous paired abseil on this version. That gives the route a social element, though you should only choose it if you and your partner both feel ready. The paired option does not remove the need to pay attention to the guide or manage the rope properly.

If that sounds like too much, the operator also offers a simpler Abseil tour for people with no experience required. That alternative is worth considering rather than forcing yourself into the more demanding format. The point is to have a good underground experience, not to prove something to the rock.

What the 2.5-hour itinerary feels like

The full experience lasts about two hours and 30 minutes. The exact rhythm will depend on the group and the guide, but you can expect a blend of orientation, fortress exploration, equipment preparation, and rope descents rather than two and a half hours of continuous abseiling.

At the start, you meet the guide and receive the equipment. All abseiling gear is supplied, certified to current standards, and checked regularly. That removes the need to bring your own harness or rope system, but it does not remove your responsibility to arrive dressed for the setting.

The underground visit comes with audio-video special effects and projection. These features add context and atmosphere as you move through the fortress. I would treat them as supporting details rather than the main reason to book. The real draw is the unusual combination of military architecture, unfinished stone, and physical activity.

The abseiling stages then give the visit its focus. The first two descents let you work with instructor support. The cascading rock provides the stronger test, with the paired descent available for those who want to share the challenge. You should expect pauses while the guide organizes equipment and checks each person’s readiness.

The experience ends back at the meeting point and includes a wine tasting. That final tasting changes the pace nicely. After a cool underground activity, a local drink gives the outing a relaxed finish instead of ending the moment you leave the fortress.

Why the small group matters

The maximum group size is eight people. For an activity involving ropes, harnesses, and uneven rock, that is a useful limit. A guide has fewer people to monitor, and you have a better chance of hearing instructions clearly and getting direct help when you need it.

Small groups do not guarantee a private experience. The tour is described as a group activity, while private tours and other dates or times are available on request. Still, eight people is a more manageable number than a large cave excursion, especially when the route includes separate descents.

You should also expect the group’s pace to affect your time underground. Some people may move confidently while others need more explanation or a slower start. That is part of the trade-off in a shared activity. The progression and instructor backup make the format friendlier to mixed ability levels, but the group will still need to stay together.

The practical clothing and footwear rules

Take the 14°C temperature seriously. The underground facilities are cool, and you should bring warmer clothing even if the day outside is hot. A light jacket or warm layer is a sensible choice, especially while you wait for equipment checks or listen to the guide.

Non-slip soles are mandatory. This is not a suggestion buried in the fine print. The cascading rock can be uneven and slippery, so the operator can refuse participation if your shoes are unsuitable. Choose secure footwear with good grip rather than smooth casual sneakers.

The operator can change or adjust the tour because of bad weather. The activity also requires adequate footwear and sobriety. Anyone under the influence of alcohol or drugs will not be accepted, which is particularly important for an activity involving heights and ropes.

The visit and entrance to the underground facilities are at your own risk. That does not mean you are left without support. Certified guides provide the instruction and equipment, and insurance is included. It does mean you should make an honest decision about your comfort, health, and footwear before booking.

Who should book this experience

I would recommend Abseil Plus to you if you want more than a standard guided site visit and like the idea of learning a physical skill in an unusual setting. It suits people who can follow instructions, tolerate enclosed underground spaces, and feel curious rather than alarmed about descending a rock face.

It is also a good choice for couples or friends who like shared challenges. The simultaneous paired descent gives you something to attempt together, and the wine tasting provides an easy way to finish the outing.

The tour is not recommended for people with epileptic seizures or claustrophobia. It is also a poor match if you dislike slippery surfaces, heights, or the feeling of being underground. The operator says most people can participate, but that broad statement should not replace your own judgment.

Families and mixed-age groups should pay close attention to the actual demands of the Abseil Plus version. The information supplied does not give a minimum age or a detailed fitness standard, so you should ask the operator before booking for a child or anyone with health concerns.

Is the price fair at $90.36?

At $90.36 per person, this is more expensive than a simple cave entrance or walking tour. You are paying for several parts at once: the guided fortress visit, certified abseiling equipment, professional guides, insurance, special effects, the rope instruction, and wine tasting.

The value depends on how much of that package you will use. If you only want to see the underground fortress, the abseiling component may feel like an unnecessary cost. If you want an active outing and would otherwise book a separate adventure activity, the price becomes easier to justify.

The small maximum group also adds practical value. A rope activity benefits from individual attention, and a group of eight should feel more controlled than a large commercial outing. Private tours and other times can be arranged on request, but the supplied information does not give their prices.

This is best viewed as a combined cultural and adventure experience. The fortress gives you a setting you would not get at a standard climbing center, while the abseiling turns the visit into something physical and memorable. The wine tasting is a pleasant extra, though it should not be the reason you book.

Meeting point and timing details to check

The stated meeting point is Adventurer adventure tours, Plase ul. 21, 51000, Rijeka, Croatia. The end point is the same meeting point. Because the experience description refers to Rovinj while the meeting address is in Rijeka, confirm the exact meeting location with Adventurer before you pay for transport or set your day’s schedule.

That location detail matters. Rovinj and Rijeka are different Croatian destinations, and you should not assume the activity begins in the town you happen to be staying in. The listed operating hours are Monday through Sunday, 9:30 AM to 5:30 PM, for the period from August 22, 2024, through December 8, 2026.

Confirmation is sent within 48 hours of booking, subject to availability. The activity is near public transportation, but the information provided does not specify the exact transit route or travel time. Give yourself enough time to reach the stated meeting point, and check the address again when your booking is confirmed.

The activity is generally available in English. Other languages are not listed.

Weather, cancellation, and booking flexibility

You can cancel up to 24 hours before the start time for a full refund. Cancellations made less than 24 hours before the start time are not refunded, and changes made inside that same window are not accepted.

Weather can affect the plan. If poor conditions force a cancellation, you will be offered another date or a full refund. The same applies if the minimum number of participants is not reached, with the option of a different date or experience.

The activity is often booked about five days ahead. That is a useful planning guide, not a guarantee of availability. Since confirmation is subject to availability, I would avoid leaving this until the last day if the experience is important to your itinerary.

Final decision: book Abseil Plus or choose the easier tour?

Book Abseil Plus if you want a small-group outing that mixes an unfinished World War II fortress, rope descents, underground projections, and wine. The instructor-supported start makes the challenge more approachable, while the cascading rock and paired descent give experienced or confident participants something extra to work toward.

Choose the no-experience-required Abseil tour if the slippery rock sounds beyond your comfort level. You will still get the underground setting and abseiling element without committing to the hardest section.

Before booking, confirm the Rijeka meeting address, bring warm clothing, and wear non-slip shoes. If you are comfortable underground and ready to follow a guide’s instructions, this is a distinctive way to see San Giovanni and do more than simply walk through it.

FAQ

Where does the tour meet?

The stated meeting point is Adventurer adventure tours at Plase ul. 21, 51000, Rijeka, Croatia. The activity ends back at the meeting point.

How long does the experience last?

The tour lasts approximately two hours and 30 minutes.

How long is the underground fortress?

The San Giovanni underground fortress is 550 meters long.

What does Abseil Plus include?

Abseil Plus includes the first two descents, a descent on the cascading rock inside the fortress, and the option to try a simultaneous paired abseil.

Do I need previous abseiling experience?

The first descents can be completed with instructor backup so you can learn the technique gradually. If Abseil Plus feels too demanding, the operator offers an Abseil tour with no experience required.

What clothing should I bring?

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

What kind of shoes are required?

Shoes with non-slip soles are mandatory for this tour.

Is the tour available in English?

Yes. The experience is offered in English.

What happens if bad weather cancels the tour?

You will be offered a different date or a full refund if poor weather causes the cancellation. A different date, experience, or full refund is also offered if the minimum number of participants is not reached.