Can You Do Two-Weapon Fighting with Booming Blade? A Deep Dive
The short answer is: generally, no. You cannot combine Two-Weapon Fighting with Booming Blade in the way you might initially expect. While both involve melee attacks, their mechanics are incompatible, stemming from the fundamental difference between taking the Attack Action and casting a spell that includes a weapon attack. Let’s break down why.
The Core Issue: Attack Action vs. Cast a Spell Action
The Two-Weapon Fighting (TWF) rule is explicitly tied to the Attack Action. It states that when you take the Attack Action and attack with a light weapon, you can use a Bonus Action to attack with another light weapon held in your other hand. This bonus action attack does not add your ability modifier to the damage roll unless you have the Fighting Style: Two-Weapon Fighting which can only be obtained by certain classes.
On the other hand, Booming Blade is a cantrip, and you cast it using the Cast a Spell Action. The spell description includes an attack with a melee weapon as part of the spell’s effects. This single weapon attack is part of the spell’s process, not a separate action, nor is it the Attack Action which Two-Weapon Fighting requires to trigger.
Therefore, when you use the Cast a Spell Action to cast Booming Blade, you are not using the Attack Action. Consequently, the Two-Weapon Fighting rule cannot be invoked, and you cannot make an additional off-hand attack as a bonus action.
Why the Confusion?
The confusion often arises because both TWF and Booming Blade involve melee attacks. However, the trigger conditions are where the mechanics diverge. TWF requires the specific Attack Action, while Booming Blade uses the Cast a Spell Action. It’s a matter of specific triggers, not just the presence of melee weapons.
Think of it this way: casting Booming Blade includes making a single melee attack, but it is part of the spell’s delivery, not the Attack Action itself.
Addressing the “Extra Attack” Feature
You might wonder how Booming Blade interacts with the Extra Attack feature, which many martial classes gain at level 5. The same principle applies: Extra Attack only applies when you take the Attack Action, allowing you to make multiple weapon attacks during this action. Casting Booming Blade, again, uses the Cast a Spell Action, not the Attack Action. Therefore, Extra Attack has no effect when casting Booming Blade.
Key Takeaway
You cannot use Two-Weapon Fighting alongside Booming Blade because Booming Blade uses the Cast a Spell Action, not the Attack Action that is required to trigger Two-Weapon Fighting.
Frequently Asked Questions (FAQs)
1. Can I make an off-hand attack if I cast Booming Blade as my first attack of the turn?
No. Even if you cast Booming Blade before you would take the Attack Action, the rule still states that the Attack Action must be used for the Two-Weapon Fighting bonus action to be used.
2. Does the Dueling Fighting Style apply to Booming Blade?
Yes. As Booming Blade requires an attack with a melee weapon as part of the spell, the Dueling Fighting Style applies if other qualifiers are met—specifically, that the weapon is one-handed and you aren’t wielding another weapon in your other hand.
3. Can I use Booming Blade as an Attack of Opportunity?
Yes, you can! If you have the War Caster feat, you can cast a spell that has a casting time of one action as a reaction. As Booming Blade has a casting time of one action it can be used to cast the spell as a reaction which includes the weapon attack as a part of the spell.
4. Can I use Green Flame Blade with Two-Weapon Fighting?
No, for the same reasons you can’t use Booming Blade. Both are cantrips that use the Cast a Spell Action, not the Attack Action, so the Two-Weapon Fighting bonus action cannot be activated.
5. Can I cast Booming Blade and then still use my Extra Attack feature?
No. Extra Attack states that if you use your action to make an attack you may make another attack. Since casting Booming Blade uses the Cast a Spell Action, not the Attack Action, the Extra Attack feature cannot be used.
6. Can I stack Green Flame Blade and Booming Blade?
No. Generally, you can only cast one cantrip per turn. However, specific class features like a fighter’s Action Surge or a sorcerer’s Quickened Spell can allow you to cast two cantrips in a single turn. However, you cannot cast both Booming Blade and Green Flame Blade on the same attack.
7. Can I use Booming Blade with a thrown weapon?
No. Booming Blade specifically requires a melee attack with a melee weapon. You cannot throw the weapon.
8. Does Booming Blade’s damage stack if I cast it multiple times?
No. The damage from Booming Blade will only trigger once, even if you cast it multiple times. The second part of the spell which triggers after the target moves will also not stack and trigger if they move for a second time.
9. Can I use Sneak Attack with Booming Blade?
Yes. Sneak Attack triggers when you hit an enemy with a melee weapon attack. When casting Booming Blade you hit the target with a melee weapon, triggering the Sneak Attack.
10. Does Booming Blade get critical hit damage?
Yes, the initial weapon attack damage from Booming Blade can be a critical hit. However, the extra damage from the spell (when the target moves) is not multiplied on a critical hit.
11. Can I combine Shillelagh with Booming Blade?
Yes, casting a combination of cantrips is fine. Shillelagh uses a bonus action to enchant the weapon and Booming Blade uses an action.
12. Does Booming Blade work with Shadow Blade?
Yes, in the current edition. However, earlier versions of the spell did not allow it. The current version specifies a “weapon worth at least 1 sp.” which the material component is of Shadow Blade.
13. Do Thunder Gauntlets work with Booming Blade?
No. Booming Blade requires a melee weapon, and improvised weapons do not gain the melee or ranged type, so Thunder Gauntlets do not work with Booming Blade.
14. Is Extra Attack better than Booming Blade?
It depends. Extra Attack is generally better for consistent damage and if you do not have an advantage on your attacks. Booming Blade can be more effective at low levels, or if you consistently have an advantage on your first attack (perhaps due to a familiar).
15. What classes are best at Two-Weapon Fighting?
Fighters tend to be the best for Two-Weapon Fighting due to having the most options to increase their damage and use their bonus action for an additional attack. Rangers, Rogues, and Bards can also make use of Two-Weapon Fighting, but fighters will be able to use it most efficiently.