written by Jana Vitoušková 25/08/2017

This lake, called Cuu Trai Cau or Tuyet Tinh Coc of Vietnam, is known for its otherworldly blue glow water and it is located in Thuy Nguyen District, Hai Phong province. It has the total area of 20 ha and it is surrounded by Tra Son Limestone.

Tuyet Tinh Coc Hai Phong Vietnam

I hadn’t heard of this unbelievable blue lake until my friend visited it and shared an amazing photo from his trip on Facebook.

Since it is only 33 kilometres from our house, we took our motorbike and went for a trip to see it with our own eyes. We had to make sure he didn’t photoshop it 😀 It took us probably an hour through small villages and rice paddies to get there.


Tuyet Tinh Coc Hai Phong Vietnam
The water’s striking blue colour is caused by the limestone rocks surrounding the quarry. The limestone leaches calcite crystals into the water, turning its colour a bright turquoise.

Tuyet Tinh Coc Hai Phong Vietnam

The “lake” boasts acidity levels of pH 11.3, just less than ammonia at 11.5pH and bleach at 12.6pH. So DON NOT TRY TO SWIM there, unless you want to risk kidney problems, fungal infections, rashes, and even blindness.

Also, there is a lady collecting a parking fee (10.000VND per bike, 50.000VND per car) and she was a nuisance. We didn’t know about the fee. We thought she is just trying her luck to get some money of us and so we pretended we didn’t understand. She was laughing with us, but then she picked up my camera bag and was slowly walking away. I told her ‘no,no,no’ and so she put it back. She then took my helmet and went into her house. Lee went to her house, bought two bottles of water and took the helmet back.

Tuyet Tinh Coc is definitely a place worth a visit to see it and take some amazing photos of the beautiful scenery.


Where to find Tuyet Tinh Coc?


More photos:

Tuyet Tinh Coc Hai Phong Vietnam

The landscapes and surroundings were just amazingly beautiful!


Smoking mountain!


Baby duck attack! 😀


  • Gosia

    I’m going to Hanoi in June, and I have to say this photos just make my day! Incredible! Can you tell a little more about your adventure with Vietnam?

    • Hi, I’m so happy it made your day. I’m sorry for my late reply but I have been a bit busy. My adventure? I’ve been working here since January 2017. When I have some time I try to see some new spots. 🙂

    • Hi, I’m so happy it made your day. I’m sorry for my late reply but I have been a bit busy. My adventure? I’ve been working here since January 2017. When I have some time I try to see some new spots. 🙂

  • Nidhi Kapur

    Fantastic write up and superb photographs! I wish I could be at Vietnam

    • thank you so much Nidhi for your lovely comment. Vietnam has an amazing nature, however the city life is not so great and it is kinda stressful. But for an adventurous holiday it is a perfect destination.

      • David Pack

        What is stressful about the city life for you?

        • shopping especially….most of the time they try to overcharge you, most small shops don’t have price tags…yesterday we wanted to buy a ticket to Cat Ba (we went there 6 times at least) every time they ask for a different price. I was pointing at their price list which they had there and they told me no, that that one is for Vietnamese…but they didn’t have one for foreigners….these situations make me stressed and upset.

  • Melanie

    Wow that lake is amazing! I loved Vietnam — we went last year for 14 days and it was just gorgeous. Sending you #gltlove 🙂

    • Thank you so much! I live here for 4 months now….I would prefer if I have more time to explore the country instead of being stuck in one ugly city 😀

  • Stunning photography!!!!!! I was surprised that the water’s PH is so high!!!!

    • Definitely not a good HP for a swim. In USA they have something similar and families go to spend their sunny days with kids there…..unbelievable! And thank you Sarah! You know me, I loooove photos :)) Tomorrow we are going to Ninh Binh and I’m super excited! So many beautiful locations!