https://worldbuilderblog.me/2015/02/24/release-the-mounts/
Riding Turtle CR: 1/2 (100 XP)
Large beast, unaligned
Armor Class: 12
Hit Points: 26 (4d10 + 4) 4d10+4
Speed:
10 ft
, swim: 50 ft
Skills:
Hold Breath. The turtle can hold its breath for 15 minutes.
Senses: Passive perception 10
Languages: -
Challenge Rating: 1/2 (100 XP)
by bloodyman88
Actions
Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 6 (1d8 + 2) piercing damage.
These enormous, freshwater turtles are large enough to hold one rider comfortably on the shell. The turtles are trained to swim on the surface, since most of their riders cannot breathe underwater, however, they can be commanded to dive and surface. Turtles like this are often used in lieu of boats when traveling on lakes and rivers.
Suggested Environments
Ignored difficult terrains; Swamp, Marsh