Hazards make up the dangerous Encounters throughout the Sea of Thieves. They can be environmental such as lightning and volcanic debris or non-environmental such as Sharks and Skeletons.
Enemies pose a threat to any player, whether you're looking for treasure on foot or swimming in open water. Enemies will target players and try to kill them by whatever means they can.
Skeletons are one of the most common enemies found on the Sea of Thieves. Skeletons commonly appear on large and small islands, often attacking in groups, and can use the same weaponry as the players. There are different types of Skeletons with different strengths and weaknesses that appear on active Forts or as part of a Bounty Voyage. Skeletons can also be found manning the crews of wandering Skeleton Ships and firing cannons from islands at passing ships.
Phantoms are common mob enemies found on large and small islands. Like Skeletons, they commonly appear in groups and can use any weaponry the player can, excluding the Eye of Reach. Unlike Skeletons, they will switch between the cutlass and a ranged weapon (they will spawn with ONLY a pistol or blunderbuss, not both) relative to combat circumstances. Additionally they can teleport and perform a charge attack. They are more versatile than Skeletons and behave in a somewhat smarter manner, though are still rather predictable.
Ocean Crawlers are common mob enemies found on large and small islands. Unlike Skeletons and Phantoms, Ocean Crawlers have three different "classes" that each have unique abilities and attacks. Some classes have supportive abilities that buff nearby Ocean Crawlers, such as a protective shield or an electric aura, making them much more difficult to defeat.
Sharks swim all around the Sea of Thieves, hunting for any live prey. Sharks will appear and start chasing a player if they stay in water for long periods of time. Groups of Sharks are attracted to combat, usually gathering around players battling a Megalodon, a Kraken, Skeleton Ships, or even other player crews.
Sirens are aquatic-based enemies that pose a threat to players in open water, similarly to Sharks. They can perform melee attacks, ranged attacks with Tridents, and can heal each other while dealing damage to players within range. Sirens are more commonly seen in The Sunken Pearl Tall Tale, but also spawn the same as Sharks in open water.
The Sea of Thieves is not only inhabited by dangerous foes, but it's filled with several environmental hazards found on and around islands.
These Statues are found on the shores of small and large Islands. The curse of these statues will continuously do 5% damage a second to any Pirate that gets too close to them.
Lightning bolts will strike random areas within a Storm, damaging players and enemies alike. Lightning can strike through a ship, damaging players both inside and under the Hull. Lightning can also blow up Gunpowder Barrels.
Traps are permanent, hazardous structures found in caverns on Sailor's Bounty and the Shores of Gold. These structures include various types of spike traps and swinging axe and log traps. These traps immediately kill a player on contact. Some of these Traps can be manually activated using levers placed on cave walls to help clear the trapped room of ambushing waves of Skeletons. Various Large Islands also have hidden trap caves that start filling up with water or waves of Skeletons until a riddle is solved or the skeletons are defeated. These caves can only be accessed by opening vaults with appropriate Totems obtained for specific Tall Tales or as a reward for completing a Wayfinder Voyage. Discovery Ridge and Plunder Valley also house rigged Stronghold Gunpowder Barrel traps, which are limited to the fifth Shores of Gold Tall Tale, The Art of the Trickster.
The Devil's Roar has it's own collective slew of dangerous hazards that accompany it's fiery landscapes. It is one of the most dangerous regions in the game and thus has many hazards exclusive to islands within that region.
Falling Volcanic Debris
These hailing Volcanic Rocks are a byproduct of Volcano eruptions in The Devil's Roar and can kill a player with full health upon impact. They also deal heavy damage to the Ship's Hull, Wheel, Capstan and Masts and blow up any Gunpowder Barrel they come in contact with. The range of an erupting volcano is indicated by falling Cinders.
Earthquakes are the byproduct of both inactive and active Volcanoes in The Devil's Roar. Earthquakes inhibit a player's movement, producing an effect similar to being drunk and limping at the same time.
Boiling Water is a byproduct of active Volcanoes in The Devil's Roar. The waters surrounding the erupting Volcano will start to boil, dealing 5% damage per second to anyone swimming or touching the water, even inside a ship. Rowboats are not affected by the boiling water, making them effective tools for accessing and escaping erupting Volcanic Islands.
Flowing lava is a byproduct of active Volcanoes on the large islands of Devil's Roar. Volcanic Rock with cracks inside them will start spewing out lava during an eruption, making much of the Islands inaccessible as it does 5% damage per second to anyone on it.
Geysers are small pressurized pockets of hot water on Devil's Roar Islands. Geysers erupt either individually or in bursts on the soft terrain of Volcanic Islands. When a player stands on a Geyser, they will be launched high in the air, which will often inflict fall damage. Skillful players can aim their landing on high ground or slopes to avoid taking damage. Most Geysers erupt more than once, making digging treasure and navigating Volcanic islands more difficult.
Players can be set on fire by explosions, either from Gunpowder Barrels or Firebombs, or from contact with a burning ship. While burning, the player slowly takes damage over time until the fire is extinguished. Fire lasts only a brief duration, but can be put out through contact with water.
There are a few sources of Venom; Snakes will spit/bite venom at players and other threats that get too close, an impact from a Venomball, contact with Kraken ink, and the toxic cloud attack of the Hermit. When poisoned by Venom, the player's screen will turn purple/black and the player will take 5 damage per second. Venom will also damage and kill Skeletons.
One of the more unpredictable hazards of the open seas are other Player Pirates and Crews. While not all players are necessarily hostile, all pirates in the Sea of Thieves are equally equipped, have equal capacities, and are controlled by actual users rather than less accurate ai enemies, making them one of the most dangerous threats in the Sea of Thieves. Overcoming these threats usually require a combination of skill and knowledge to outwit and outplay them.