Skip to Content

An Ecotour in St Thomas at Cas Cay Mangrove Lagoon

EcoTour in St Thomas at Cas Cay Mangrove Lagoon

Posts may be sponsored. Post contains affiliate links. I may be compensated if you make a purchase using my link.

I’ve been to St. Thomas on six different occasions. This US Virgin Island always seems to find its way on my Caribbean cruise itinerary. I’ve spent the days there relaxing on beautiful beaches, gone snorkeling in St. John, and hopped on a local ferry to nearby Water Island. While planning this voyage aboard the Caribbean Princess, I was browsing the cruise line’s excursions page and the word, “Ecotour” grabbed my attention. Typically, I like to book excursions independently with local tour companies for smaller groups, cheaper prices, and generally, better experiences. However, this time around, I booked the Wildlife Sanctuary, Kayak, Hike, and Snorkel tour through Princess Cruises. The tour company offering the excursion was Virgin Islands Ecotours, seemingly the only company offering an ecotour in St Thomas. Booking directly with Virgin Islands Ecotours would have only saved us $5 each in this case, and we would have had to find our own way to their headquarters.

The day before we reached St. Thomas, we were notified that the Caribbean Princess would no longer be docking at Crown Bay or Havensight docks. Instead, the cruise ship would be anchored off the shore of Charlotte Amalie and we would be taking the tender boats across to the island. This was one instance where I was relieved that I didn’t book an independent excursion. For those who had planned to meet their private tour guides at the dock, they had to somehow get in touch with the tour guides to inform them of the change (which isn’t easy when you’re at sea). As for us, we actually really enjoyed anchoring off the coast. First of all, there were no delays to catch a tender in the morning for our tour. It was fully organized by the cruise ship staff. Robyn and I went to the Princess Theatre in the morning at our designated meeting time and we were given a sticker with our tour number on it. We waited with the other cruise ship passengers who were taking the tour, which ended up being about 20 people. Our excursion was limited to 20 people and did sell out well in advance, so I highly suggest that you reserve this one ahead of time on the Princess Cruises website. We all boarded a tender together and sailed across to downtown Charlotte Amalie. Here was the other perk about being anchored off the shore: we were right downtown! If we had docked at Crown Bay or Havensight, we would have had to take an open-air taxi to the downtown area if we felt like going to a restaurant or doing some shopping.

While we were waiting by the pier, an older Rastafarian man with very long dreadlocks came up to our group and said, “Ecotour? Snorkeling, kayaking? Come with me!”. I started to follow behind him, as did a couple of other people. Suddenly, I heard a lady yell out, “NO! Don’t go with him! He isn’t with our tour!”. I think she thought that he was trying to get us to take a different tour other than the one we had booked. I doubted myself for a second and wondered if I was silly, trusting a random person who asked me to go with him. Then, I thought, how would he know that we were waiting for an ecotour? We had stickers on our shirt that only had a number on them. As only half of the group seemed to want to follow the man and there was some confusion, a cruise line employee came over and instructed us to go with him – he was our open-air taxi driver! We boarded his very decked out open-air taxi – I wish that I had a photo of it. It was a brightly decorated red, green, and yellow vehicle. We took a short drive around the winding streets of Charlotte Amalie to the Virgin Islands Ecotour marina.

Kayaking the Mangrove Lagoon

After a quick safety lesson and explanation of where we would be visiting, we were ready to kayak around the Mangrove Lagoon. Many of our belongings were left behind as we didn’t want them to get wet, and they were locked up safely in a storage locker. We boarded the tandem kayaks. Yes, the kind that you share with another person. As our tour guides joked, “We’re tour guides, not relationship counselors!”, they can be both fun and frustrating to navigate depending on your partner. Thankfully, we had way more fun than frustration. Robyn and I had a great system going where she sat in front and led the paddling. Left, right, left, right. If she wanted to paddle more on one side, she would yell out, Left! or Right! And with that, we didn’t want to murder each other. Instead, we breathed in the fresh air and admired the mangrove forest that surrounded us as we paddled down the waterway. Giant roots extended from the shoreine and down into the water below. We learned how important mangroves are to our natural environment in tropical and subtropical regions.

  • Healthy mangrove forests are vital to a thriving marine ecology as their fallen leaves and branches provide nutrients for those living in this natural environment.
  • Many threatened and endangered species are native to mangrove forests including: manatees, sea turtles, monitor lizards, and many more.
  • Mangrove forests are a nursery for juvenile fish and other species. They are also a site for nesting, migratory resting, and feeding for hundreds of species of birds.
  • Less than half of the world’s original mangrove forest remains today, mostly due to clear cutting for shrimp farms. They are disappearing more quickly than tropical rainforests, with very little attention given to this growing problem.

Though we didn’t see very many birds while kayaking, this protected area is a large habitat for resident and migratory birds on the island. This region would be fantastic for anyone interested in bird-watching. It really was such a peaceful area with calm waters, ideal for kayaking. We kayaked our way towards Cas Cay, a wildlife sanctuary island off the coast of St. Thomas.

Cas Cay Wildlife Sanctuary

We left our kayaks along the shores and hiked along a forest path on Cas Cay. Cas Cay is a deserted 15-acre tropical island, compromised of mangrove forests to the south and volcanic cliffs to the north. Our first stop was just off the shore to see all of the hermit crabs. They truly are fascinating creatures and they were everywhere! From above, they looked like small shells, scurrying across the forest floor. I was really worried that people were going to step on them, but our guide reassured me that their shells are extremely strong. In fact, they can withstand 500 pounds of pressure! Even if someone stepped on top of one, it wouldn’t be enough weight to injure the crab or its shell. St Thomas Ecotour at Cas Cay Mangrove Forest and Wildlife Sanctuary At this point, our guides asked us to participate in a “Hermit Crab Race”. A small circle was drawn into the soil and people were instructed to carefully pick up a hermit crab and place it in the middle of the circle. As our tour leader yelled, “GO!”, we watched to see whose hermit crab would crawl outside of the circle first to win the race. I wasn’t sure how I felt about this. I didn’t really like how an Ecotour company encouraged its guests to pick up the creatures for our own amusement. Instead of participating in the race, I observed the hermit crabs that were crawling around the ground and the trees. I really enjoyed how knowledgeable the guides were in explaining the significance of the hermit crabs in the mangrove forest. Apparently, hermit crabs “upgrade” their shells up to three times a year, discarding their old one for a carefully chosen new one. Hermit crabs are also nature’s meteorologists; we can tell what the weather is going to be like by how far the hermit crabs have climbed up the tree trunks! Don’t get me wrong: the hermit crab race wasn’t directly harmful in any way, though it may have been stressful for some of the crabs. I thought it was more fascinating to watch them crawl around on their own.

We continued our hike down the forest path, as our guides pointed out some of the local flora. There is a very poisonous tree that grows in St. Thomas called the Machineel tree. We were informed that all contact with this tree should be avoided as the leaves, bark, and fruits contain a caustic sap that can seriously injure or kill a person. Christopher Columbus called the fruit of the Machineel tree the “Death Apple” after several of his men ate the fruit. The sap can also cause permanent blindness if it gets into your eyes.

Mostly on this hike, we admired the view from Cas Cay looking out to the surrounding wavy waters. The ocean water crashed against huge boulders and volcanic rocks along the shore, with the water filtering into the calmer areas where we originally kayaked. It had started to rain, though we were in our bathing suits and were already slightly wet from the kayaking. We were going to be in the water soon enough snorkeling, so the rain water really didn’t matter. I thought that the hazy atmosphere in the rain was very pretty. I’m sure that this place looks simply gorgeous on a sunny day, though the rain delivered a rather enchanting aura.

St Thomas Ecotour at Cas Cay Mangrove Lagoon Wildlife Sanctuary St Thomas Ecotour at Cas Cay Mangrove Lagoon Wildlife Sanctuary

Red Point Blow Hole

One of the highlights of the short hike was witnessing the spectacle at the Red Point Blow Hole.  A blowhole is a geologic formation in which a wave enters the mouth of a sea cave and is pushed upwards towards a cavity existing above, resulting in a powerful blast of water. With the short rain storm we experienced, the waves were crashing furiously against the cliffs and water was fiercely spraying into the air. Though we did spend a good amount of time here, I could have watched this beautiful scenery all day.

St Thomas Ecotour at Cas Cay Mangrove Lagoon and Wildlife Sanctuary St Thomas Ecotour at Cas Cay Mangrove Lagoon and Wildlife Sanctuary St Thomas Ecotour at Cas Cay Mangrove Lagoon and Wildlife Sanctuary

Snorkeling at Cas Cay

We hiked back towards our kayaks and grabbed our snorkel gear: it was time to explore the underwater areas around the mangrove forests out to sea. It was a very unique area to snorkel. Swimming away from the shore, it appeared as though there were only a few coral reefs here and there. There were many volcanic rocks buried beneath these waters that provided great hiding spots for the fish. There was a large variety of fish, some I had never seen while snorkeling in the past. For instance, I saw a HUGE porcupinefish that was massive compared to all of the other fish. Another unique fish that I spotted was a Spotted Trunkfish that glided through the water with ease. Robyn even saw a very unique carnivorous plant. It looked like a very normal reef plant, though when our guide skimmed the surface of it, the plant contracted at a rapid pace to trap its prey. You can see all of those fish and plants in the video posted above. Though we didn’t see any that day, others in our group saw barracudas, and on other occasions, stingrays, small sharks, and octopus have been seen at this snorkeling site. I didn’t consider St. Thomas to be such a thriving spot to snorkel in the Caribbean. I highly recommend donning your snorkel mask and swimming around Cas Cay. At the end of our snorkeling trip, we swam by the mangrove forests to observe their extensive roots intertwined beneath the surface of the water, which was home to numerous species of juvenile fish. St Thomas Ecotour at Cas Cay Mangrove Lagoon and Wildlife Sanctuary

St Thomas Ecotour at Cas Cay Mangrove Lagoon and Wildlife Sanctuary

St Thomas Ecotour at Cas Cay Mangrove Lagoon and Wildlife Sanctuary

The HUGE porcupinefish that dominated all of the other fish in size!

At the end of the day, we kayaked back to where we began and got a taxi ride back to downtown Charlotte Amalie. I highly recommend this tour. It was great to see a less-traveled side of St. Thomas when there can be several cruise ships in port, It was very quiet and peaceful here, even with a couple of tour groups. Furthermore, we were seeing a region of St. Thomas that was largely untouched and preserved. The tour guides were very knowledgeable and the trip was very educational. It felt great to be active on a tour getting a bit of a workout with the kayaking, hiking, and snorkeling.

Virgin Islands Ecotours Booked through Princess Cruises; several tours are available in St. Thomas and St. John through their website:


Take an Eco-Tour in St. Thomas: Kayaking and Snorkeling at Cas Cay

Have you visited St. Thomas or the US Virgin Islands? What was your favorite activity or place to visit there?


This site uses Akismet to reduce spam. Learn how your comment data is processed.

travel His world

Wednesday 27th of March 2019

I love the under water shots. What kind of camera did you shoot those with? I am in the market for waterproof cameras at the moment


Thursday 28th of March 2019

Just a regular ol' GoPro Hero 3! We've since upgraded to the GoPro Hero 5 Black and they produce way better photos. I think there's a GoPro 7 or 8 out by now, too!

Meg Jerrard

Tuesday 21st of April 2015

Sounds like a really fun day, and the snorkelling looks amazing. Haha my partner wouldn't like the idea of a tandem kayak because apparently that would leave him doing all of the work for the two of us :D So lucky to have been to St Thomas 6 times, if you've been returning that frequently I'll have to get my act into gear and make it there at least once! Thanks Lauren!


Monday 20th of April 2015

Love those snorkelling pics!

Mary {The World Is A Book}

Saturday 18th of April 2015

This looks like such a great excursion. We've been to St. Thomas a couple of times and really like it. We'll be sure to do this next time. Love the video and photos.

Cathy Sweeney

Friday 17th of April 2015

Hermit Crab Races? Sign me up! :) Actually, there are many things about the things you saw and did on this tour that appeal to me. However, I've been a little reluctant to try kayaking. I'm sure someone could convince me to do it. St. Thomas was the very first Caribbean island I ever visited. Also my first ever "warm weather while it was snowing in Chicago" trip. It was heavenly.

This site uses Akismet to reduce spam. Learn how your comment data is processed.