When is the best time to dive Ojamo Mine?

The best months to dive Ojamo Mine are January, February, March, April, May, June, July, August, September, October, November, December, when conditions are most favorable.

What certification do I need to dive Ojamo Mine?

Ojamo Mine requires a minimum certification of Advanced Open Water. Currents are typically mild and the maximum depth reaches 55 m.

How much does it cost to dive Ojamo Mine?

A 2-tank dive at Ojamo Mine averages around $100 USD. The destination is in our mid range tier.

What will I see diving Ojamo Mine?

Ojamo Mine is known for none — flooded mine environment, with 15–40 m visibility and 4–6°C water temperatures.

Why does Ojamo Mine score 53.8/100 on OkToDive?

Ojamo Mine earns a 53.8/100 Score based on 12 weighted categories including marine life, coral health, visibility, operator quality, and value. Backed by 135 operator reviews.

Ojamo Mine Diving — Score: 53.8/100 | Conditions, Operators & Guide

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World Class

Advanced

Ojamo Mine

FinlandEurope

53.8

SCORE

60.2500°N

24.0700°E

Ojamo Mine is a flooded limestone quarry near Helsinki offering astonishing visibility that can exceed 40 metres in its frigid, gin-clear water. Submerged tunnels, mining equipment, and even a sunken forest create an eerie overhead environment. Drysuit and overhead training are mandatory.

Finland's Crystal-Clear Underground Lake

Visibility15–40 m

Temperature4–6°C

Max Depth55 m

Currentmild

2-Tank Dive$100

Best MonthsJanuary, February, March, April

CertificationAdvanced Open WaterAdvanced

Score Breakdown

Click any score to see a detailed breakdown

Marine Life

10.0

Species diversity, megafauna encounters, reef fish abundance, macro life, and endemic species.

Species Diversity

Megafauna Encounters

Reef Fish Abundance

Macro Life

Endemic Species

Marine Life Diversity

10.0

Coral & Reef Health

5.0

Visibility & Conditions

88.0

Dive Site Variety

50.0

Water Temperature

15.0

Depth & Access

70.0

Operator Quality

78.0

Topside Experience

55.0

Getting There

72.0

Value & Cost

65.0

Crowding

80.0

Social Proof

58.0

Key Species

none — flooded mine environment

Dive Types

cavefreshwatermine

Traveling with Non-Divers?

Your non-diving travel companions will find plenty to enjoy topside while you're underwater. Here are some activities to consider.

Activities for Non-Divers

Helsinki day tripLohja old townTytyri Mine Museum

Nearby Cultural Sites

Tytyri Mine Museum
Lohja Church

Non-Diver Partner Score

4/10

Limited topside — plan ahead for non-diving partners.

Family FriendlyNot recommended

Restaurants & Nightlifebasic

Safety & Emergency

Dive Insurance

Dive insurance is essential. Standard travel insurance often excludes scuba diving. We recommend DAN (Divers Alert Network) for comprehensive dive accident coverage.

Learn More at DAN.org

Hyperbaric Chamber55 km — Helsinki University Hospital Hyperbaric Unit

Nearest Hospital10 km

Chamber at Helsinki University Hospital (Meilahti); local ambulance ~10 min

Skill LevelAdvanced

Current Strengthmild

Top Operators

Ojamo Dive Center

TDI

4.7

80 reviewsNITROX

Helsinki Dive Club

CMAS

4.5

55 reviewsNITROX

Compare This Dive Site

Honest reality check

What your dive shop won't tell you

The minimum certification printed on a brochure is the legal floor, not the honest recommendation. Here's what we actually think you should bring to this site.

Recommended logged dives

65+

Below this we'd send you somewhere easier first.

Recommended certification

Cavern Diver minimum. Full Cave certification for anything past the daylight zone.

“Intermediate minimum — deep profiles and variable viz.”

What will challenge you

→Recreational limit of 40 m is reachable here (max depth 55 m). Gas planning and NDL tracking matter.
→Cold water — 4°C at the coldest. Drysuit recommended; wetsuit divers will be genuinely cold past 30 minutes.
→Overhead environment. Standard recreational training does not cover you past the entrance. People die here doing what they'd do on an open reef.
→Variable visibility
→Deep profiles

What will surprise you

→Permit-restricted access. Daily cap: 12 divers. Book 6+ months ahead through a licensed operator.
→Ojamo Mine has more marine life variety than most divers expect
→Local operators know spots the guidebooks miss

Time of day

When to dive it

Every dive shop gives you this briefing at 7am. We just wrote it down. Tidal dependency: slight. Optimal window: First light to 11am for best visibility..

Morning

Viz
peak
Current
mild
Crowd
light

reef exploration
photography

Best light and calmest conditions before afternoon wind picks up.

Afternoon

Viz
moderate
Current
mild
Crowd
moderate

drift diving
second tank

Wind chop can reduce viz. Still diveable but morning is better.

Month-by-month

Dive forecast

Realistic conditions by month. Viz ranges are what you should actually expect, not best-case marketing numbers. Confidence % is the share of days that match this profile historically.

Month	Viz (m)	Temp (°C)	Current	Sea	Rain	Confidence	Highlights
Jan	15–28	4	Mild	Mod	Light	70%	peak season crowds
Feb	15–28	4	Mild	Mod	Light	70%	peak season crowds
Mar	15–28	4	Mild	Mod	Light	70%	peak season crowds
Apr	15–28	4	Mild	Mod	Light	70%	standard conditions
May	33–40	6	Mild	Calm	Dry	70%	standard conditions
Jun	33–40	6	Mild	Calm	Dry	70%	standard conditions
Jul	33–40	6	Mild	Calm	Dry	70%	standard conditions
Aug	33–40	6	Mild	Calm	Dry	70%	standard conditions
Sep	33–40	6	Mild	Calm	Dry	70%	standard conditions
Oct	15–28	4	Mild	Mod	Light	70%	standard conditions
Nov	15–28	4	Mild	Mod	Light	70%	standard conditions
Dec	15–28	4	Mild	Mod	Light	70%	standard conditions

Shoot here

Photography brief

Subjects are only half the shot. A perfect macro site is useless in a three-knot drift, and a wide-angle dream is useless at 35 m with a murky ceiling. These are the conditions, not the hype.

Macro subjects36

Wide angle34

Viz stability88

Hover friendliness100

Natural light0

Recommended kit

→Two independent light sources minimum; video lights beat strobes in caverns
→Cold-water housing — condensation is a real issue below 18°C, bring silica packs

Level up here

What this site will teach you

The dives that made you a better diver are the ones that made you uncomfortable for the right reasons. Here's what this site will quietly train you for.

Deep diving comfort
advanced
Regular dives past 30m build confidence at depth.
Self-reliant navigation
foundational
Shore entries mean you plan your own dive.

What it costsEstimates — calibration pending

7-day trip, per person

Rough ranges anchored to existing regional data — not booking quotes. Land-based trip, standard breakdown.

Budget

$1,800–$2,600

Hostels, shore diving, cheap eats

Flights (RT from US): $540–$660
Accommodation / day: $50–$100
Diving / day: $90–$100
Food / day: $30–$55
Transfers + misc: $50–$150

Mid-range

$2,850–$4,350

3-star hotels, standard boat ops, mix of restaurants

Flights (RT from US): $810–$990
Accommodation / day: $120–$220
Diving / day: $100–$130
Food / day: $65–$110
Transfers + misc: $50–$150

Splurge

$5,150–$8,350

Top resorts or liveaboards, premium operators

Flights (RT from US): $1,450–$1,750
Accommodation / day: $260–$500
Diving / day: $130–$170
Food / day: $130–$250
Transfers + misc: $50–$150

Flights priced round-trip from a major US hub. Figures are per person on a shared room. Solo travelers add ~30% to accommodation.

Pair with

Build a trip around it

Most divers fly across the world for one destination and don't realise another worth-it site is 90 minutes away. Here are the honest pairings.

Best dive types here

Ojamo Mine Diving — Finland