Swimming with whale sharks in Mafia Island

Swimming with whale sharks in Tanzania was always going to sound like a dive of epic proportions.

This encounter would eclipse the time I swam with whale sharks off the coast of Mexico in the Caribbean Sea. Not to say it wasn’t great (it was amazing) but it was almost like a mass whale and tourist party in comparison to the experience I had off the coast of Mafia Island in the Indian Ocean.

Swimming alongside these humble creatures is truly a remarkable moment and one you should definitely put on the bucket list. This one-of-a-kind rare encounter is one of Mafia’s great draw cards, as it joins only a handful of spots in the world that enjoys a whale shark migration.

Remarkably, this tiny island attracts the world’s longest exodus with 100 plus resident whale sharks spotted five months a year from September to February in the depths of Tanzania’s biggest and oldest marine park, Mafia Island Marine Park (MIMP). Interestingly enough, just like zebras, whale sharks have their own distinct ‘finger prints’ with their bodily patterns unmatched with any other whale shark.

Guide me the way to whale shark glory

Only a handful of tour companies operate tours to swim with these gentle giants including responsible marine tour company Kitu Kiblu. There were no more than four boats heading off into the sea of oblivion, searching for a glimpse of the world’s largest fish. Impressively, these gentle ocean giants can reach up to five to 20 metres long on average and weigh roughly 19,000 kilograms. I recalled how I felt last time swimming with them, feeling like I was size of a Barbie Doll with them graciously swimming towards me, thinking it may also try to eat me! Lucky for us all, they do not like the taste of humans and are more than happily to live off a plankton diet.

It goes way over my head as to how the captain figures out where the whale sharks may be lurking around but it isn’t looking for the giants themselves, rather searching for ‘boils.’ According to the Whale Shark and Oceanic Research Center, boils are caused when school of tuna herd smaller fish into a ball. The forced into tight knit schools and leap to the surface to escape. It is here that plankton are found in these boils and since whale sharks have a soft spot for all things plankton, there is a good chance to spot a whale shark feeding if there is a boil around. Spotting these boils are extremely difficult so props to the captain for being very skilful and having a good eye to spot them!

The rules

Our tight knit boat crew (10 people max) was told that we must do what is commanded of us without delay. We were advised that once the captain yells out ‘Now!,’ that is when you respond to their command without hesitation and jump off the boat (left or right depending on what side the whale shark is on) and snorkel your way over.

We were advised to put on our snorkel and let our fins dangle off the side of the boat so that we could quickly get into Olympic swimmer mode to savour this golden moment. My lady manners were out the window as jumping in with flippers on the side of the boat was not going to be a pleasant sight – especially when climbing back on board the boat with my limbs flying everywhere! People probably saw more than they bargained for after all, it was a whale shark they wanted to see and not my lady parts almost in view!

If you missed out on your chance to dive in, the boat would slowly manoeuvre to get close to the big shadow that countless swimmers were chasing on moments later.

All fins are out once a whale shark is spotted from the boat with us all frantically jumping into the water. Unlike Mexico, there is no limit to how many people are swimming in the water at the same time trying to get a glimpse of the shark.

One, two three jump!

My first jump in was like a mad rush at a Boxing Day sale. Everyone was out for themselves and making a lunatic dash to see this gentle giant. If a judge had to give me a score out of ten for my bulls eye jump into the water to see the whale shark, I would get a ten. Once I recovered from my leap, I had the whale shark right under me. I felt so small. I wanted to keep looking at it underneath but I had so much water in my snorkel that I struggled to breathe so out I popped my head above water. I was desperate to get my shit together for another sighting down under. Once I recovered, I popped my head and body back down and there she (or he) was, looking ever so gracious, swimming slowly with its tail moving in a hypnotising-like ‘left to right’ manner.

My wishful thinking Olympic freestyling talents were just a mere fantasy as soon enough, the whale shark sped past and into oceanic oblivion.

The second leap of faith from the boat proved to be more successful than the first. Besides the feeling of filling my lungs with sea water (OK, slight exaggeration), I had the whale shark metres under me for a longer period – and all to myself! My new found ocean friend and I were gliding the waters together, alone without another swimmer in sight. I was its Little Mermaid sidekick and the finest under the sea moment I could ever wish for.

There was another swim where I had looked up with only one other person that managed to keep up the pace. On other swims, the whale shark in true movie like fashion, was gliding through the perfect rays of light casted down into the waters. It was truly a harmonious sight seeing the water sparkle and looking at this massive whale shark right in front of me.

In a nutshell

I think by the end of it I had about four to five close encounters with the two whale sharks we had spotted and kept chasing. One swim I felt super close to hitting the edge of its propeller-like tail so I decide to back of a little – As if I could ever keep up the pace!

Feeling small in the world is sometimes a daunting feeling but seeing these great beasts of the ocean is truly momentous and certainly worth dipping your toes into the ocean for.


Mafia Island Lodge – beachside location, incredible staff and food to dine for.

Getting there

Coastal Aviation flies to Mafia Island from multiple ports – Dar Es Salaam and Zanzibar. Win for you also as a trip to Mafia feels like a joy ride as you get treated to the sight of beautiful blue hues.


Kitu Kiblu offers respectful and sustainable encounters swimming with these precious giants. Service and knowledge was top notch and I would certainly book with them again!

Disclaimer: I travelled as a guest as a part of a super adventurous tour of Tanzania with Mafia Island Lodge and Coastal Aviation.