Mention travelling in Tanzania and chances are you'll be quizzed on which safari reserve you're visiting. Yet this East African marvel harbours just as much diversity off its shores. Contrary to those who like to spend their holidays on dry land, my recent visit to Tanzania took me on an underwater safari around the exotic Spice Islands off the coast: Pemba, Zanzibar (Unguja) and Mafia Island. Here, I discovered muck dives rivalling Indonesia and human-sized marine species, with Robinson Crusoe - albeit very luxurious - surface intervals to boot...

nudibranch

Nudibranch Bingo in Southern Pemba

My journey began on the northernmost island of Pemba. While often overlooked in favour of its famous neighbour, Zanzibar, Pemba has more spectacular diving. To the south, diving largely centres around Misali Island. Misali offers some beautiful sloping walls, where diving amid fields of lettuce corals (Turbinaria) interspersed with staghorn corals (Acropora) and ginormous boulder corals (Porites) is commonplace. Nestled within the corals you can find moray eels, while schools of colourful chromis and spunky damselfish dance above. You'll also catch glimpses of reef fishes like lyretail hogfish and regal angelfish, as well as charismatic anemonefish guarding their home and eggs.

There are gifts for macro lovers too. Nuzzling amongst anemones, it's common to spot porcelain crabs and various kinds of cleaner shrimp. Misali offers an excellent opportunity to play 'Nudibranch Bingo,' so you should brush up on your ID skills of nudibranch species; from vividly patterned Chromodoris to sponge-like Phyllidia and technicolour Nembrotha nudibranchs. Planarian flatworms are also rife on the reef. The diving in the south is best accessed from Fundu Lagoon, a secluded retreat nestled on the mangrove-lined shores of southern Pemba.

Leafy Scorpion Fish

Shore Diving in Northern Pemba

Diving in the north of Pemba Island encompasses two distinct areas. The first is the house reef and near reef, which run along the shores of The Manta Resort. The second area comprises the far reef sites of the Njao and Fundo Gaps. These far reef sites offer deeper dives with stronger currents, making them suitable only for confident and experienced divers. However, the currents in these areas bring a wealth of nutrients, resulting in thriving coral gardens and attracting larger species like Napoleon wrasse, tuna, trevally and stingrays.

At the house reef and near reef sites around The Manta Resort, soft corals dominate the landscape, as well as hard corals forming fascinating bommies structures. During my dives, I spent almost 25 minutes circling around one particular bommie on the house reef, mostly because of the large population of leaf scorpionfish on it! Every time I photographed one, another would appear nearby, and in a huge array of colours, from red to pink, white, yellow, burgundy and purple.

One site - Shimba Hills - consists of two parallel reefs separated by a sand channel. Here a mix of things can be seen, from elusive frogfish and Zanzibar whip coral shrimp to well-camouflaged crocodile fish and schools of sweetlip fish. Needless to say, the diving at Pemba left a lasting impression.

Frogfish

Best for Beginners: Zanzibar

Next stop: Zanzibar (otherwise known as Unguja). Perhaps the best known of all three islands, Zanzibar, with its powder-white sand beaches, is perfect for beginner divers and non-divers. Diving off the East Coast is centred around Mnemba Island, accessible from the Boutique Villa Kiva or Zanzibar Pearl Resort, both conveniently located within walking distance of our diving partner.

Mnemba Island is a popular diving spot, so expect to share the waters with other dive boats. However, the underwater world here doesn't disappoint, with sightings of grouper, Napoleon wrasse, giant frogfish, crocodilefish and schools of snapper. Geometric eels also hide amongst the corals, and we even spotted a group of sleepy whitetip reef sharks resting under one of the overhangs. While the coral may be lacking, macro lovers can keep an eye out for minute critters like tiger flatworms and pipefish.

Shaun the sheep nudibranch

Muck Diving off Mafia Island

My final stop brought me to the most breathtaking of all three places: Mafia Island. This inconspicuous island is one of the most unique places I have ever dived, mostly because Mother Naturedecides when and where you can enter the water. As Mafia Island is highly tidal, the diving here does not run on a set schedule so flexibility is key. But don't worry, the wonderful team at Mafia Island Diving will take care of everything, you just show up and enjoy your dives.

Mafia Island offers three shore dive sites, which are a veritable haven of macro-life, rivalling world-famous spots like Dumaguete in the Philippines or Lembeh in Indonesia. While Mafia does not offer 'true' muck diving - a dark-coloured bare seabed - the quality of macro critters is up there. It's a promise that if you don't see a seahorse on one of your dives, a beer is owed to you - we saw 15 on one dive! Beyond seahorses, you will also find frogfish, pipefish, waspfish, Indian walkers, sea spiders and shrimp. There's also a mind-boggling number of nudibranch species, including the neon green leaf sheep nudibranch (Costasiella kuroshimae), or 'Shaun the Sheep,' and the hooded nudibranch (Melibe leonia). This was also my first time seeing a sacoglossan sea slug (Cyerce elegans) and a guitar ray.

stingray

The Best Diving in Tanzania: Kinasi Pass

Away from the shore, you don't want to miss a drift dive at Kinasi Pass. This thrilling site comprises a sand channel leading into Kinasi Wall, where you'll encounter large stingrays resting on the sandy bottom and massive groupers reaching human-sized proportions (think: six feet tall). As you continue through Kinasi, schools of barracuda and trevally will surround you and curious Napoleon wrasse might indulge you by in coming closer. Don't forget to take in the colourful butterflyfish and angelfish as you drift along.

The dive will end with the current gradually declining, and you will find yourself in the beautiful Coral Garden. Here, you will hover over fields of staghorn and plate corals (Turbinaria), topped with clouds of iridescent chromis and orange anthias. Like me, you may be lucky enough to witness a giant moray eel being cleaned by diligent cleaner wrasse while sharing your safety stop with two potato groupers.

Most dive sites around Mafia Island are conveniently accessible within a 30-minute boat ride, making it an ideal destination for all levels of divers. You can stay at charming lodges like Kivulini, Kinasi or Pole Pole, or even get to experience staying in a treehouse at Chole Mjini.

My message: get yourself to these Tanzanian islands! They offer some of the best diving in Africa, yet remain wonderfully under the radar.