Photo by Mikhail Vedyokhin · CC BY-SA 2.5
Cavern
Cavern is the entry-level overhead-environment course, limited to the cavern zone — within sight of natural light and a direct exit — rather than a true cave. It introduces line use, buoyancy control, and the discipline of moving through an overhead space before a diver commits to real cave training. It's for open-water divers curious about overhead diving, or planning to progress into Intro to Cave and Full Cave, who need the foundational skills first. It's deliberately conservative — TDI keeps cavern divers within reach of natural light specifically so the stakes of a mistake stay low while the fundamentals are learned. No fixed depth beyond the cavern light-zone limit; 4 dives and 80 minutes of accumulated bottom time at 2 different sites required.
Centres that teach this course
18 dive centres in the directory publish a price for this exact certification, checked Sep 2026. Each centre's own wording is shown beneath its name. Ranges cover whole-course prices only — where a centre charges per day or per dive, its rate is listed separately below, since a daily figure is not comparable with a course total.
- $950total
- $1,320total
- $600total
- $870total
Charged by the day or dive rather than as a course price:
- $325per day
- $300per day
- Cave AdventurersUnited StatesCavernPrivate class$450/day→ $900 for the 2-day minimumGroup class$350/day→ $700 for the 2-day minimum each$450per day
- Under The JungleMexicoCavern Diver (TDI)private$345/day→ $1,725 for the 5-day minimumper diver in a group$295/day→ $1,475 for the 5-day minimum each$345per day
- Go Dive MexicoMexicoCavern diverprivate$330/day→ $1,650 for the 5-day minimum2+ divers$300/day→ $1,500 for the 5-day minimum each$330per day
- $350per day
- $235per day
- THB 20,000total
- THB 35,000total
- THB 35,000total
- MX$15,000total
- MX$9,500total
Charged by the day or dive rather than as a course price:
- €300per day
Charged by the day or dive rather than as a course price:
- Air Dive AlorIndonesiaCavern1 student, privateIDR 3,200,000/day→ IDR 6,400,000 for the 2-day minimum3 studentsIDR 2,400,000/day→ IDR 4,800,000 for the 2-day minimum eachIDR 3,200,000per day
Same training under a different agency
17 centres
A separate set of centres, teaching Cavern under a different agency. These are not the same certification — the standards and the card differ — but they cover the same depth and scope, which is why centres price them alike. Every row here names whose rating it is, and none of them is counted above.
- $750total
- $600total
Charged by the day or dive rather than as a course price:
- $275per day
- Protec MexicoMexicoCavernPSAI1 student$420/day→ $2,100 for the 5-day minimum2+ students$370/day→ $1,850 for the 5-day minimum each$420per day
- $295per day
- $330per day
- $300per day
- ByMoMoDiveMexicoCavern DiverIANTD1 student$245/day→ $980 for the 4-day minimum3 students$205/day→ $820 for the 4-day minimum each$245per day
- THB 29,000total
- THB 29,000total
- THB 30,000total
- THB 29,000total
- THB 29,000total
- THB 20,000total
- THB 20,000total
- €1,000total
- €1,000total
- €800total
Same tier, agency not stated
4 centres
These centres publish a price for Cavern, but their own wording does not say which agency's certification it buys — many teach several and name the card only once you enquire, and some price one course for either agency. The figure is comparable; the certification is not identified, so we do not guess at one.
- $600total
- $500total
- €800total
- €450total
These prices are not like-for-like. Two centres can charge very differently for the same certification because they include different things. One price may cover twinsets, stages, deco gas and cylinder rental for every training dive, a dedicated classroom for the theory, boat or transport to the site, and the agency's registration and materials; another may be tuition only, with all of that charged separately — or the other way round, with a centre bundling in extras the first leaves out. Class size, whether the course is one-to-one, and how many days are allowed for it move the figure too. Check what each centre's price includes before comparing them, and confirm with the centre before booking.
Consumables are usually extra. Sorb, helium, O₂ and other fills, park and cenote fees, certification fees and rental are commonly charged on top.
Packages combining several certifications, upgrades from an existing one, and open-ended day rates are excluded — none of them is the standalone price of this course, and including them would move the figures away from what a new student can actually book.
Prerequisites
Open Water Diver, minimum 25 logged dives, minimum age 15.
Instructors Teaching This Course
Mexico
United States
Thailand
Indonesia
Philippines
Other locations
Dive Centres Offering This Course
Mexico
United States
Thailand
Indonesia
Malta
Philippines
We're still building out the directory country by country, so this list isn't every instructor or dive centre teaching it in the world — more locations are coming soon.
Common questions about TDI Cavern
How much does TDI Cavern cost?
Published prices for TDI Cavern range across 9 centres in the TecDiveTools directory — roughly US$500 to US$1,350 at current exchange rates. In each centre's own currency: $600–$1,320 (4 centres), THB 20,000–35,000 (3 centres) and MX$9,500–MX$15,000 (2 centres). 9 centres charge by the day instead, which is not comparable with a course total. Prices differ mainly in what they include, so compare the inclusions before comparing the numbers. Prices were last checked in September 2026.
How long does TDI Cavern take?
Between 2 and 5 days, based on the durations 17 centres publish for it. The time depends on the centre's schedule, weather, and how quickly the required skills are demonstrated — agencies set a minimum number of dives, not a fixed number of days.
What are the prerequisites for TDI Cavern?
TDI's standards require: Open Water Diver, minimum 25 logged dives, minimum age 15.
What is the minimum age for TDI Cavern?
TDI's standards state: Minimum age 15.
How many dives do I need before starting TDI Cavern?
TDI's standards state: Minimum 25 logged dives.
What is the equivalent of TDI Cavern in other agencies?
At the same tier in TecDiveTools' cross-agency comparison: ANDI Cavern, RAID Cavern, PSAI Cavern Diver, IANTD Cavern Diver, NSS-CDS Cavern Tech Diver, SSI XR Extended Range Cavern Diving and NSS-CDS Single Tank Cavern Diver. They cover comparable training, but each agency sets its own standards, depth limits and certification card, so they are comparable rather than interchangeable — check which one your next course accepts.
What course comes after TDI Cavern?
The next step in TDI's progression is TDI Intro to Cave.
Where can I take TDI Cavern?
138 dive centres and 194 instructors in the TecDiveTools directory teach TDI Cavern across 6 countries, most in Mexico, the United States, Thailand and Indonesia. Each is listed further up this page.
Does the price of TDI Cavern include gas and equipment?
Not always — it varies by centre. Certification fees, equipment rental and boat or site fees are commonly charged on top of the course price. Each centre's price list on TecDiveTools shows what it notes as included.