How to Identify Marine life
Our PADI Underwater Naturalist specialty course is an excellent 1-day course that teaches scuba divers how to identify fish, invertebrate, and common plant species and upon completion will earn you a PADI Underwater Naturalist specialty course certification.
Understanding the Aquatic Environment
With the information this course provides, you will be able to recognise and explore the marine life commonly seen in the ocean around Koh Tao.
Knowing how to identify fish species, invertebrates, and plant species will add real value to your dives and provide you with a deeper understanding of the marine environment and the animals that live there.

Included in Underwater Naturalist Specialty course
- 2 Underwater Naturalist Open Water training dives
- PADI Underwater Naturalist Manual
- AWARE – Our World, Our Water
- Dive Insurance
- Max 4 students per PADI Dive Instructor
- Full set of Aqualung rental equipment including a Dive Computer for your course
- Official Isla Tortuga Divers T-shirt
- PADI certification card
Prerequisites for the Underwater Naturalist course
- Minimum certification: Open Water Diver
- Minimum Age: 10 years
- Recent diving experience – scuba review if you have not dived in the last 12 months
- Medically fit to dive
During your training, we will build your confidence and skills at your own pace, as you become proficient at the marine life identification techniques taught throughout the course.

1 Day Underwater Naturalist Specialty course
Our PADI Underwater Naturalist Specialty course is conducted over two sections; theory and practical, and the course includes two Open Water training dives.
Both training dives allow divers to practice their marine life identification techniques whilst gaining the fundamental knowledge required to better understand species interactions and marine ecosystems.
Knowledge Development
- Students need to attend all the instructor-led knowledge development sessions and complete the knowledge reviews with your specialty diving instructor.
Open Water training practical sessions – 2 Open Water training dives
Learning Objectives for Underwater Naturalist course
Our PADI Underwater Naturalist Specialty Course provides students with the knowledge and skills required to become an informed and responsible marine protector and underwater explorer.
Aquatic Ecology Fundamentals: Gain a solid understanding of the key differences between aquatic and terrestrial ecosystems, including factors like pressure, light penetration, and nutrient cycles.
Major Marine Life Groupings: Learn to identify and understand the ecological roles of major marine life groupings like fish, invertebrates, algae, and corals.
Symbiotic Relationships: Explore the fascinating world of symbiosis, where different organisms live together in mutually beneficial relationships.
Predator-Prey Interactions: Uncover the dynamics of predator-prey relationships in the ocean, including hunting strategies, defence mechanisms, and their impact on the ecosystem.
Underwater Behaviour: Learn to recognise and understand various underwater animal behaviours, like communication, feeding strategies, and reproductive patterns.
Responsible Diving Practices: Develop and refine buoyancy control and other diving techniques to minimise your impact on the underwater environment.
Local Marine Life Identification: Gain knowledge about the specific marine plants and animals found in your diving region, enabling you to identify them on your dives.
Threats to Marine Ecosystems: Explore the major threats facing our oceans, such as pollution, habitat destruction, and climate change.
Conservation Efforts: Understand current conservation efforts and how divers can contribute to protecting the underwater world.
Scientific Observation Techniques: Learn basic techniques for observing and recording marine life sightings in a way that can contribute to global citizen science efforts.
By working through these learning objectives, you will become a citizen scientist contributing valuable information to global coral reef marine conservation efforts.

Open Water training dives for Underwater Naturalist course
Your Underwater Naturalist specialty training dives will be conducted at suitable dive sites around Koh Tao. The choice of dive sites will depend on multiple environmental factors including weather and our current diving schedule.
Information for PADI Underwater Naturalist course
Our Underwater Naturalist Specialty course provides students with the knowledge and skills required to become competent divers who can identify fish, invertebrates, and plant species.
PADI Underwater Naturalist course Schedule
You will meet your diving instructor at 9am ready for the orientation and instructor-led knowledge reviews, which includes completion of your paperwork and the PADI medical statement.
09:00 – 11:00: Orientation & Knowledge Development
12:15 – 17:00: Two Underwater Naturalist Open Water training dives
Upon completion of all the course requirements you will be certified as an Underwater Naturalist specialty course diver.
The instructor-led knowledge review is conducted on the first morning before the dives and consists of a twenty-question open book knowledge review that your instructor will review with you.

Underwater Naturalist Course Topics
- Discover the meaning of Ecology and Ecosystem
- Taxa and how scientists classify organisms
- How to classify organisms into different categories
- Understand the different types of Symbiosis
- Common misconceptions people have about aquatic organisms
- Learn of the differences between terrestrial and marine ecosystems
- How to minimise your impact underwater when taking photos
- Human interactions with marine life
Underwater Naturalist course – Open Water training dives
There are two Open Water Underwater Naturalist Specialty course training dives to complete at popular dive sites around Koh Tao.
Underwater Naturalist Dive 1 in Open Water
On dive 1, your diving instructor will assess your buoyancy to ensure your diver skills are good enough to be collecting marine organism data around coral reefs.
After evaluation of your buoyancy skills and we are confident they are good enough, using your marine life identification slates, you will be asked to passively observe marine life and take notes.
By the end of dive 1, students will be able to:
- Passively observe marine life whilst demonstrating good buoyancy skills
- Demonstrate and apply best diving practices to minimise any impact on marine dwelling organisms and the marine environment.
- Locate and identify at least two aquatic plants
- Locate and identify at least four aquatic invertebrates
- Locate and identify at least five aquatic vertebrates
Underwater Naturalist Dive 2 in Open Water
On dive 2 open water training dive, you will plan the dive with your instructor and by the end of this dive, you will be able to:
- Passively observe aquatic marine life
- Demonstrate and apply best diving practices that preserve bottom-dwelling organisms and minimise any impact on the marine environment.
- Find and identify examples of symbiotic relationships and predator/prey relationships.
- Find and identify as many human impacts on the marine environment that you can on your dive.
After completing both the underwater naturalist dives, your instructor will debrief on everything you have learned and discuss any problems encountered on the dives and how it can be improved next time.
Upon completion of two Underwater Naturalist specialty course Open Water training dives and meeting all the course requirements, you will be certified as a PADI Underwater Naturalist specialty diver.

Benefits of the PADI Underwater Naturalist course
The PADI Underwater Naturalist Specialty Course will transform your scuba diving experiences from recreational dives into exploration dives of the delicate marine ecosystem.
This course is perfect for divers who want to take their diving and marine environment knowledge to the next level and go beyond observing marine life and learn more about how it all works together.
Key Points of the Underwater Naturalist course
Enhanced Awareness: You will gain a deeper understanding of the marine environment, including the key differences between aquatic and terrestrial ecosystems, and their interactions.
Sharper Observation Skills: The course hones your ability to identify various marine plants and animals, allowing you to see marine life you may have missed.
Discover Hidden Behaviours: Learn about symbiosis (mutually beneficial relationships), predator-prey interactions, and other fascinating behaviours that shape the underwater world.
Responsible Diver: The course emphasises responsible diving practices, ensuring you minimise your impact on the delicate marine environment.
Local Ecosystem Knowledge: Gain in-depth knowledge about the specific ecosystem of your diving area, making your dives even more meaningful.
Greater Appreciation: With newly discovered knowledge, you will develop a deeper appreciation for the beauty and complexity of the underwater world.
Marine Conservation Advocate: The course empowers you to become an ocean ambassador, understanding the threats marine ecosystems face and looking at ways to protect them.
More Rewarding Dives: Every dive becomes a discovery mission, transforming familiar dive sites into exciting opportunities to learn and observe.
Connect with Other Divers: The course encourages a sense of community with other divers who share your passion for the underwater world.
PADI Course Requirements: The Underwater Naturalist Specialty course can contribute towards the PADI Master Scuba Diver rating (check with your instructor for details).

Become an Underwater Naturalist specialty diver
By taking this course, you will become a knowledgeable and responsible underwater naturalist, which will help to make your dives more enriching and help to contribute to the protection and conservation of our oceans.
Build on your knowledge and skills as a scuba diver and sign up for the PADI Underwater Naturalist specialty diving course and make a difference.
Koh Tao is a great location to go fun diving and explore our PADI Specialty courses. With our expert diving instructors, PADI Divemasters, custom dive boat and quality dive equipment, Isla Tortuga Divers can meet the needs of all certified divers.
Contact us for fun dive pricing, our AC Rooms or Shared Rooms and our daily dive site schedule.