Charge. If the sea horse moves at least 20 ft. straight toward a target and then hits it with a ram attack on the same turn, the target takes an extra 7 (2d6) bludgeoning damage. If the target is a creature, it must succeed on a DC 11 Strength saving throw or be knocked prone.
Water Breathing. The sea horse can breathe only underwater.
Actions
Ram. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeoning damage.
How many giant sea horses for a fight?
A giant sea horse is worth 100 XP. Using the 2024 encounter budgets (SRD 5.2), this is how many giant sea horses fit each difficulty for a party of four characters of the same level. A dash means even one would be over the budget.
Party level
Low
Moderate
High
1st
2
3
4
2nd
4
6
8
3rd
6
9
12+
4th
10
12+
12+
Budgets add up every monster’s XP, so you can swap some for other creatures of the same total. Try other party sizes and mixes in the encounter calculator.
How the giant sea horse compares at CR 1/2
Against the 32 other challenge 1/2 monsters in the SRD 5.1, the giant sea horse has more hit points than 4 of them, which makes it one of the frailest at its CR. See every CR 1/2 monster.
Statistic
Giant Sea Horse
CR 1/2 average
Armor Class
13
12.4
Hit points
16
21
Best attack bonus
+3
+4
2024 stat block: Giant Seahorse
The 2024 Monster Manual revised the giant sea horse, and the SRD 5.2 carries the new stat block. What changed:
It’s called the Giant Seahorse in the 2024 rules.
Armor Class: 13 → 14.
Speed: 0 ft., swim 40 ft. → 5 ft., swim 40 ft..
Ability scores: STR 12 → 15, DEX 15 → 12.
New in its stat block: Bubble Dash.
Gone from it: Charge.
Armor Class
14
Hit Points
16 (3d10)
Speed
5 ft., swim 40 ft.
Challenge
1/2 (100 XP)
STR
DEX
CON
INT
WIS
CHA
15 (+2)
12 (+1)
11 (+0)
2 (-4)
12 (+1)
5 (-3)
Senses
passive Perception 11
Languages
None
Traits
Water Breathing. The seahorse can breathe only underwater.
Actions
Ram. Melee Attack Roll: +4, reach 5 ft. Hit: 9 (2d6 + 2) Bludgeoning damage, or 11 (2d8 + 2) Bludgeoning damage if the seahorse moved 20+ feet straight toward the target immediately before the hit.
Bonus actions
Bubble Dash. While underwater, the seahorse moves up to half its Swim Speed without provoking Opportunity Attacks.
