If you’re wondering about venomous snakes in Bulgaria, then you’ve come to the right place. This guide will dive right into the world of slithering serpents in this corner of the eastern Balkans, all to help you get a grip (not literally, of course!) on the reptiles you’ll probably most want to avoid between party sessions on Sunny Beach and sightseeing bouts through Sofia.
There’s good news and bad news. The good is that snakebites in Bulgaria, as in virtually the whole of Europe, are WAY less common than in Asia and Central America. What’s more, the venomous snakes in Bulgaria also tend to be a lot less venomous than ones found in more exotic climbs. The bad news is that there are still at least five species you’ll want to be wary of, including Europe’s deadliest viper. Yikes!
Generally speaking, the chance of an encounter with venomous snakes in Bulgaria will go up in the warmer spring and summer months. Those are the main mating periods and when creatures like the adder appear on trekking paths basking. You’re also most likely to cross paths with one of the critters listed below if you’re planning on venturing to more rural corners of the country, away from the buzz of Sofia and Varna.
Common European adder (Vipera berus)

The Common European adder kicks off this list of the most venomous snakes in Bulgaria. And why not? It’s by far – just as the name implies – the most regularly sited venomous snake in the whole of Europe. They live all over, from the beaches of the UK to the hills of Normandy in France, the wilds of southern Scandinavia to the Black Sea regions of the Balkans. And, yep, Bulgaria is there too – these guys reside all over the country, bar some parts of the coast.
Their ubiquity is down to their ability to adapt to a whole host of habitats. From sandy dunes to beech woods, riparian fields to alpine meadows, the common adder is pretty good at making a home in a whole range of various settings. There’s that, and the fact that most females are able to bear litters of up to 20 young at once!
Bulgaria actually has its own recognized sub-species of the Vipera berus. It’s known as the Balkan adder and has the Latin moniker Vipera berus bosniensis. Recent studies of their toxicity have revealed that they might just have a more potent venom than their comapdres over in Western Europe and could be capable of causing serious symptoms like interference with the nervous system.
Generally speaking, this snake is relatively easy to identify. A thick-set body that’s colored black or brown is also topped with a very clear diamond and zigzag pattern that runs the whole way from head to tail. They’re often shy but can be confrontational. The main seasons for adder spotting are the spring and the summer.
Horned viper (Vipera ammodytes)

Beware the horned viper. This is the deadliest snake in Europe when you consider only the potency of the venom. That, by extension, also makes it the deadliest of all the venomous snakes in Bulgaria. And it’s not just the power of the juice they’ve got hidden away. It’s also the length of the fangs that should set the alarm bells ringing – these guys have teeth that grow up to 15mm in length, meaning they can inject their concoctions deep into the blood system without any trouble at all.
There’s even worse news for those traveling to the home of happening Sunny Beach and rakiya tipples: Horned vipers live ALL over Bulgaria. Yep, it’s thought that this snake inhabits every corner of the nation, from the craggy hills of the Rhodope Mountains in the southeast all the way to the ridges around Sofia in the northwest.
Perhaps the one saving grace is that the horned viper should be relatively easy to spot and identify in the wild. The initial clue will be the horn itself. It protrudes right out from the end of the nose, growing to just over a centimeter and coming to a tip before the length of the body. You really can’t miss it. Then there’s the coloration – females tend to be brown and beige, males grey and black. There’s also a backwards V marking on the top of the head.
Aspic viper (Vipera aspis)

Also known as the asp viper and the European asp, this species inhabits a large swathe of southern and central Europe. The epicenter of their range is actually the Alps, northern Italy, and the heartlands of France. However, many scientists now think that there are potential populations to be found further east in the Balkans and Bulgaria.
So, what are you looking for? This is a typically viper-style snake with a diamond-shaped head and protruding scales above the eyes, topped off with a noticeably curled nose. They grow to something in the region of 65cm at full adulthood and the males tend to be the longer of the two sexes. Coloration wise, these guys are usually wood brown with black cross markings.
The venom of an aspic viper is worse than that of the common European adder. In fact, it’s estimated that around 4% of untreated cases would end fatally. Symptoms of the toxic bite can be as varied as necrosis of the flesh and renal failure. The good news is that studies have shown that the most venomous sub-species of this type of snake are found in Switzerland, not Bulgaria.
Meadow viper (Vipera ursinii)

The Meadow viper is often mistaken for the common European adder. Only it’s MUCH rarer than its ubiquitous cousin and is now even listed as an endangered species by the IUCN. However, there remain healthy pockets of populations of the Vipera ursinii across much of the heart of Europe, with individuals recorded in Kyrgyzstan and Kosovo, Italy and Iran. They’ve also been seen in Bulgaria, where they tend to inhabit the cooler northern portions of the country.
The males are smaller than the females of the species, with most specimens hitting something between 60cm and 85cm in length at full adulthood. The body sports 19 regimented rows of dorsal scales and a coloration that goes from tan to black, coming with the trademark adder-style zigzag and diamond pattern on the top.
True to their name, Meadow vipers love to live in alpine and pre-alpine meadow regions below 3000 meters above sea level. For that reason, they are known to thrive in places like the foothills of the Italian Dolomites but also on the northern ridges of the Central Balkan National Park and the highlands of the Vratsa Balkan in Bulgaria.
Meadow viper bites are pretty mild when compared to other types of vipers. They tend to cause localized pain and swelling and some potential holistic effects. However, we’d still recommend seeking medical attention right away if you think you’ve fallen victim to a bite!
Montpellier snake (Malpolon monspessulanus)

The Montpellier snake is one of the least worrying of the venomous snakes in Bulgaria. In fact, for all intents and purposes, you can basically consider this one to be totally safe. The only recorded cases of it envenomating humans comes from incidents when people have inserted their finger right into the back of the mouth of the creature. You can hardly blame them for biting!
There are a few things that reduce the risk here. First, the Montpellier snake is a rear-fanged snake. That means the teeth that inject the venom are hidden away deep in the skull and rarely come close enough to human flesh to do any damage. Second, the venom itself is pretty mild. Most cases result in local symptoms like swelling and redness that can often be resolved with good monitoring and basic medication. Finally, Montpellier snakes are chilled individuals, eager to avoid confrontation and rarely quick to strike.
It’s actually thought that the species originated somewhere in North Africa. However, today, it’s main range is in Europe, going from the costas of sunny Spain all the way to the southern regions of the Balkans. They have limited habitats in Bulgaria itself but are mainly seen along the lower foothills of the Rhodope Mountains and amid the leafy Struma Valley.
Growing up to two full meters in length, the Montpellier snake remains one of the largest of all the venomous snakes in Bulgaria. It’s known for its yellow, black, and brown tricolor patterning and small head that tapers to a point. They usually feed on small lizards and rodents.
Venomous snakes in Bulgaria – a conclusion
There’s only a handful of venomous snakes in Bulgaria but we still think it’s a good idea to know which species you might encounter in this part of the globe, particularly if you’re planning rural adventures to the Balkan Mountains and backcountry. Probably the most dangerous of the snakes here is the horned viper, which is the deadliest snake in the whole of Europe. Then you have the European adder, which has a sub-species in Bulgaria that’s thought to be more dangerous than its cousins in Western Europe.