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Over-under split shot at a mossy cavern entrance — a rebreather diver in a drysuit holding a canister light in clear turquoise water

Donarun Das

Engineer-Diver. From first breath to 100m.

TDI Trimix · Sidewinder CCR · PADI Staff Instructor

15+

Years Diving

TDI

Trimix Instructor

PADI

Staff Instructor

Sidewinder

CCR Instructor

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Donarun Das standing in a dry cave in full cave-diving kit and helmet lights, smiling, stalactites overhead

Meet Donarun

A mechanical engineer who teaches diving — from first breath to 100m.

Donarun Das is a TDI Trimix and KISS Sidewinder CCR instructor based in India, also certified as a PADI Staff Instructor. A mechanical engineer from NIT Silchar turned full-time diving professional, he brings 15+ years in the water and a stubbornly analytical approach to teaching divers across the full spectrum — first-time recreational students through advanced rebreather and trimix.

Most courses he teaches are run privately — usually 1:1 or 1:2 — and built on physics, physiology, and methodical skill repetition rather than checklists. He leads expedition projects in Lakshadweep's deep walls and the cave systems of Meghalaya, and writes about decompression theory, gas planning, and the failure modes nobody wants to teach.

A quick career sketch

  1. 2010

    Engineering, NIT Silchar

    Mechanical engineering; later R&D at BHEL on CFD and turbine systems.

  2. 2011

    First certification

    Open Water with SSI. The start of 15+ years in the water.

  3. 2016

    Instructor qualifications

    PADI instructor — and then progression towards IDC Staff Instructor.

  4. 2023

    CCR & Trimix specialist

    TDI Trimix and KISS Sidewinder CCR instructor — for deep, decompression, and expedition diving.

  5. Ongoing

    Exploration projects

    Meghalaya cave systems, Lakshadweep deep walls, across Maldives.

Teaching credentials

  • TDI Trimix Instructor
  • PADI Staff Instructor
  • Kiss Sidewinder Instructor
  • PADI Tmx90 Instructor
  • Cavern Instructor
Read the full story → Train with Donarun

From the water

Recent dives & projects

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Training & Courses

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Recreational

Open water through advanced diving

Foundational certification and skill development.

 Fundamentals

Precision skills and buoyancy mastery

The bridge between recreational and technical diving.

 Technical

Trimix, CCR, and deep exploration

Advanced training for serious depth work.

From the Depth Notes

Read all posts →
Sepia-toned vintage photo of an early bulky wrist-worn dive computer with multiple digital LCD readouts and a toggle switch, strapped to a forearm
equipment

Dive Computers: How They Actually Work

June 5, 2025 · 8 min read

What your dive computer is really doing under the display: how it remodels your nitrogen every few seconds, what each reading means, and the setup mistakes that turn a safety tool into a liability.
A lit sparkler throwing white sparks with a glowing orange and blue burning tip against a black background
physiology

CNS Oxygen Toxicity

May 31, 2025 · 14 min read

Why the oxygen that keeps you alive can trigger a seizure underwater: what's really happening in your brain, the numbers that keep you safe, and why the famous warning signs don't actually warn you.
physiology

Inert Gas Narcosis

May 29, 2025 · 9 min read

What narcosis really does to your brain at depth, why the martini rule undersells the danger, and how nitrox and helium change the picture.

Ready to go deeper?

Talk to me about your next course, rebreather training, or expedition.

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