In Skull and Bones, mortars are among the most powerful ship weapons for dealing massive area damage, making them essential for fleet battles, world events, and high-level PvE encounters. However, finding the right mortar blueprint can be challenging because each tier is tied to different regions, merchants, infamy levels, and currencies.

Whether you are upgrading your ship for endgame content or looking for stronger artillery options, knowing where to find every mortar blueprint can save significant time. This guide covers all major mortar blueprints, from the early-game Mortar I to powerful endgame weapons like La Fléau.

Why Mortars Are Important in Skull and Bones

Mortars allow captains to attack enemies from a distance while dealing explosive splash damage across multiple targets. Compared with standard ship weapons, mortars are especially effective against:

• Enemy fleets grouped together
• Fort defenses
• World events with multiple hostile ships
• High-level PvE encounters

As you progress through the game, stronger mortar variants become available, but unlocking them requires higher infamy ranks and access to specialized merchants.

Players who want to accelerate their ship progression often look for Skull and Bones Items to obtain useful resources and upgrades more efficiently, especially when preparing for difficult endgame activities.

Skull and Bones Mortar Blueprint Locations

Mortar blueprints are divided into two main categories: base-tier weapons purchased with Silver and advanced/endgame weapons requiring special currencies such as Pieces of Eight and Sovereigns.

Base Tier Mortar Blueprints (Silver Currency)

Early mortar upgrades are mainly obtained through regional merchants and require Silver along with specific infamy levels.

Mortar I Blueprint Location

The first major mortar upgrade can be purchased from the Blacksmith in Telok Penjarah, located in the East Indies region.

Requirements:

• Reach Brigand infamy rank 
• Have enough Silver available
• Travel to Telok Penjarah and visit the Blacksmith

The Mortar I blueprint is a strong early upgrade that provides better explosive damage compared with basic ship weapons.

Mortar II Blueprint Location

For the next upgrade, players need to travel to the Ruined Lighthouse outpost in the East Indies.

The Mortar II Blueprint can be purchased from local faction merchants at this location. It provides improved damage output and prepares your ship for tougher encounters.

Advanced and Endgame Mortar Blueprints

Higher-tier mortars require access to the Helm Black Market and endgame currencies. These weapons are designed for experienced captains who have reached the highest infamy ranks.

Mortar III Blueprint

The Mortar III Blueprint is one of the most important endgame upgrades.

Details:

Players can purchase this blueprint from:

• Yanita Nara in Sainte-Anne
• Houma Nara in Telok Penjarah

After reaching Kingpin infamy, visit either Helm Black Market manager and exchange Pieces of Eight for the blueprint.

Mortar III offers significantly improved damage and is a recommended upgrade for players focusing on late-game naval combat.

Leopold III Blueprint

The Leopold III Blueprint is another powerful mortar option available through endgame progression.

Sources include:

• Helm Black Market
• Weekly rotation through William Blackwood in Sainte-Anne

Players will need Pieces of Eight to purchase this blueprint when it becomes available.

Because William Blackwood’s inventory rotates, checking regularly is important if you are specifically hunting for the Leopold III blueprint.

La Fléau Blueprint

For captains searching for the strongest mortar options, La Fléau is one of the most valuable choices.

This poison-based mortar can be obtained through:

• William Blackwood’s Shop
• Helm Black Market

Purchase requirements include seasonal endgame currencies such as Sovereigns.

La Fléau is especially useful for players who want additional damage-over-time effects and stronger control during large-scale battles.

Mortar Ammo Blueprint Location

Having a powerful mortar is only useful if you have enough ammunition. Fortunately, players can craft their own mortar ammo after obtaining the correct blueprint.

Mortar Bomb Crate Blueprint

The Mortar Bomb Crate Blueprint can be purchased from:

• Beach vendor at the Necropolis outpost

Finding the vendor manually can be difficult, but players can use the Blacksmith crafting menu to track the blueprint. Selecting the item will automatically place a map marker on the vendor’s location.

This makes maintaining your mortar supply much easier during long voyages and extended combat sessions.

Tips for Unlocking Mortar Blueprints Faster

Increase Your Infamy Rank

Many powerful blueprints are locked behind infamy requirements. Focus on activities that provide infamy rewards, including:

• Completing contracts
• Defeating enemy ships
• Participating in world events
• Exploring dangerous regions

Reaching Kingpin rank is especially important because it unlocks access to some of the strongest endgame equipment.

Save Pieces of Eight and Sovereigns

Advanced mortar blueprints require rare currencies. Avoid spending these resources on unnecessary purchases until you have secured important ship upgrades.

For players focused on quickly building a powerful fleet, Buy Skull and Bones Silver can help cover early progression costs and reduce the time spent farming basic resources.

Check Weekly Merchant Rotations

Some valuable blueprints, such as Leopold III, may appear through rotating vendors. Visit William Blackwood regularly to avoid missing limited-time opportunities.

Best Mortars to Prioritize

Mastering Mortar Upgrades in Skull and Bones

Mortars are a key part of a successful ship build in Skull and Bones, but unlocking every blueprint requires careful progression through regions, merchants, and currencies. Early upgrades like Mortar I and Mortar II help strengthen your ship during exploration, while advanced weapons such as Mortar III and La Fléau provide the firepower needed for endgame battles. By tracking merchant locations, improving your infamy rank, and managing currencies wisely, you can build a devastating naval arsenal and dominate the seas.