As my plane dips below the clouds and comes in to land, I'm transfixed by what's outside my window. Or rather, what's not outside my window. All I can see, for miles and miles, is lush, unbroken rainforest. No electricity pylons, no roads, and few signs of human presence at all.

This could be because my destination, Belize, has a population of around 370,000, and a population density of just 14 people per square kilometre. London has a whopping 5,491, so you can see why it looks so absolutely untouched.

But then again it might also have something to do with the fact that Belize remains under the radar of most tourists. So under the radar, in fact, that some people I speak to before I leave aren't even sure where it is.

Yet we Brits should know better – known as British Honduras until 1981, it's a former British colony. The result is a culture that feels more Caribbean than Latin, particularly when it comes to the food (you'll find several variations of rice and beans), the laidback vibe, and the Belizeans' soft, West Indian-accented English.

You could call Belize a late bloomer in comparison to its better-known neighbours – Mexico to the north, Guatemala to the west and south, and the Caribbean to the east. While it's long been popular with backpackers and divers – it boasts the largest barrier reef in the Western Hemisphere, as well as the awe-inspiring Blue Hole sinkhole 70km from the mainland – tourism is only just beginning to take off, with visitor numbers shooting up from fewer than 900,000 in 2013 to more than 1,115,000 in 2015. And with flights from Atlanta or Miami to Belize both clocking in at under three hours, it's not as hard to reach as you might think.

Belize boasts the largest collection of ancient Maya sites in the world

Slow development has its advantages, though: the government has enforced a unique tourism policy that runs hand-in-hand with its sustainability programme, which means Belize is fast becoming one of the world's leading eco-destinations. It remains largely chain-free, whether that's accommodation, food, or shops; and any new expansion is undertaken with the rainforest in mind – not to mention the ancient Maya ruins hidden within it. Belize has the largest collection of Maya sites in the world, which I can't wait to discover – not least because, for now, they're almost tourist free.

I see this first hand on my first day, when I'm exploring Xunantunich (Mayan for 'stone woman', named after a ghost said to roam the area), the remote ruins of a major city not far from the Guatemalan border. Aside from my group, there are only a few other small clusters of people on the whole site, despite the recent discovery of the biggest tomb of a Maya king ever uncovered. Where else can you roam around the vestiges of a lost civilization and stumble across ancient artefacts almost completely on your own?

Sadly I don't make any major archaeological discoveries, but I do soak up everything I'm told by our tour guide as I huff, puff, and sweat my way to the top of El Castillo in sticky 35°C heat. My cursing halts as I take in the view: the 40m tall structure stands in the middle of six plazas surrounded by 26 temples and palaces, together forming a site that demonstrates the Maya knack for town planning, even in the seventh century. It's truly incredible. But this seems to be par for the course when it comes to Belize.

We make our way back to our hotel the same way we came: on horseback. Our guide is the owner of Hanna Stables, Santiago – the son of a British nurse who was stationed in Belize, he went to Reading and Manchester universities before working in food security for the UN for a decade.

Iguanas at the sanctuary at the San Ignacio hotel

The iguana sanctuary at the San Ignacio hotel

I'm not the most elegant rider, so Santiago reels off information about the country to distract me from the task at hand. Two hours of riding later, we're back at the San Ignacio Resort, where I spend the night. It's a cool and calm oasis away from the humidity, set in 17 acres of land that are home to 99 of the 150 bird species native to Belize, which is known for being a popular destination for keen bird watchers.

In addition to its pool, tennis courts, and spa treatments, the luxury resort has another, slightly more unusual attraction: a green iguana sanctuary, where dedicated staff take injured and orphaned iguanas, nursing them back to health and/or maturity before releasing them into the wild.

I meet Ziggy, who has a bone disease that gives her a hunched tail; Stargazer, who suffered untreatable brain trauma; and Gnome, the resident mascot iguana, whose easygoing nature means that he's used to educate school children about the now-endangered species that's rapidly dwindling thanks to a local penchant for eating its eggs.

In the morning, I'm introduced to Belizean breakfast staples: johnny cakes – dense, scone-like buns, made with coconut milk or cream; and fry jacks, a cross between a samosa and a croissant. I pocket a few extra deep-fried treats to keep me fuelled for the next leg of our trip: the journey to Punta Gorda, a coastal town that's a four-hour drive to the south along the absolutely stunning Hummingbird Highway, which meanders alongside rural villages and the imposing backdrop of the Maya Mountains.

As we head further south, the brilliant sunshine eventually turns to rain – unsurprising, since the southern Toledo district is the wettest area in the country. But the rain doesn't detract from the pared-back beauty of our next host, the BlueBelize guesthouse, set in verdant gardens overlooking the sea.

Run by local Esme Gordon, it's simple but comfortable, with whitewashed walls and tiled floors. Each room has access to a veranda or terrace, the perfect spot to watch dusk fall over the tropical vegetation. It's peaceful and homely here – a quality you'll experience throughout much of the country, as accommodation revolves around guesthouses rather than hotels – and the ideal place to unwind after a long day travelling.

That evening, we eat at nearby local hangout Asha's Kitchen, watching the moon rise from the wooden veranda over the water and enjoying another Belizean staple: Belikin beer. Dinner is white and flakey lionfish – a dish that tastes even better when I learn I'm helping the ecosystem by eating it, as the spine-covered predator poses one of the greatest threats to the area's marine biodiversity. Well-fed, I fall asleep listening to the rain pattering against the palm trees in the garden.

The rain continues the next day, and having admired the rainforest so much from the comfort of the plane, I'm less enthusiastic when I'm actually in it, ankle-deep in mud and semi-effectively brandishing a banana leaf as an umbrella. Today we're visiting an organic cocoa farm, run by Eladio, a local of Maya descent. We've been brought here by Bruno Kuppinger – one of several people I meet who left a high-level job to move to Belize, this time trading in banking to work in the tourist industry. Thanks to government policies aimed at preserving local jobs, he had to give up his German citizenship in order to do it. It's a serious commitment, and a mark of how special Belize is to many people.

Undeterred by the deluge, Eladio leaps around his farm, feeding us purple corn, ginger, turmeric, palm hearts and cocoa beans taken straight from the plants, and enthusing about Belize's natural larder. His farming technique is unusual: 'crops' are planted by animals and birds spreading the seeds; he and his family just cultivate and harvest them. We reach a clearing, where Eladio shows us there was once a Maya ball court, even producing an ancient stone bat. "This is where my ancestors lived," he tells us passionately. "I'll never leave it."

Eladio is just one of many – 30,000 of Belize's population are of Maya descent, and can be divided into three groups: Mopan Maya, Kekchi Maya and Yucatec Maya, each speaking a different language. Much of the Maya culture has been preserved, and today you can undertake a 'living experience', where you stay with a Maya family and learn about their customs.

Our packed and sweaty Cessna traces a stunning route over the bluest sea

Eladio offers this cultural experience at his family home, but today we're just sampling a traditional Maya lunch – a spicy chicken broth – and meet Eladio's wife and daughters, who show us what they do with the cocoa beans, producing chocolate and other products. We try the traditional hot cocoa drink that Eladio drinks every day, which, he says, is what has helped him maintain his health and vitality.

From here, we head straight to a tiny airport to board an internal flight. About 15 people are loaded into a very small airplane, which then zooms off to Belize City, where we change planes to fly to the final stop of our trip, San Pedro on Ambergris Caye. Our packed and sweaty Cessna traces a stunning route over the bluest sea; I see atolls, reefs and clusters of little islands below.

Ambergris Caye is a fairly well-known part of Belize; it's the country's largest island, and San Pedro, its main town, is the gateway to the area's diving, and for those who wish to visit the 124m-deep Blue Hole.

In stark contrast to Eladio's farm, the town is the most touristy place I've seen in Belize so far: it's packed with resorts and everyone whizzes around in golf carts, which is both hilarious and terrifying. It's also the place young Belizeans go for spring break, with all the bars and clubs that come with it.

But don't let that put you off: it's still a must-do here, not least for its beaches. Once my group arrives at our final destination, Ramon's Village Resort – a Bora Bora-inspired, self-contained oasis of thatched cabanas – my first port of call is the sea, where I float on my back and watch the sky slowly turn from blue to orange to black.

Our final day is more relaxing than those before it, spent at sea, on board a catamaran (unironically) named YOLO. Part party boat (complete with free bar and pounding music) and part snorkel cruise, its crew are friendly and knowledgeable about local marine life.

Getting There

Delta flies from London Heathrow to Belize with a layover in Atlanta from £551 return; Belize Revealed offers tailor-made holidays to Belize; Rooms at Blue Belize start at £66 per night; Rooms at San Ignacio Resort Hotel start at £199 per night; Rooms at Ramon’s Village start at £120 per night;

We see sharks, turtles and rays, snorkelling through crystal-clear waters. It's not for everyone – there are crowds of boats at some snorkelling hotspots – but it's a truly beautiful way to see Belize, and heading out on the water is a must-do, whether you're a seasoned diver or not.

That evening, we cap off the trip by eating utterly delicious street food from The Truck Stop, a static market just outside the town of San Pedro that's run by Chicagoan Ben Popik – yet another person to have decamped to the Belizean paradise. As well as hosting three traders, Popik uses the space to show films, put on a farmer's market and throw occasional parties.

Having arrived in Belize in search of ancient Maya structures, I'll admit I wasn't expecting something this modern and, dare I say it, hipster.

Yet, as I slurp Vietnamese pho in a shipping container surrounded by tropical vegetation, I decide I don't mind – it encapsulates Belize's dedication to preserving the past while embracing the new. I'll raise a Belikin beer to that.