Sharktronic Sand Sub is a Beach zombie introduced in Plants vs. Zombies 3. It first appears as a Shark Costume Zombie until it is revealed and cannot be damaged until it attacks. Sharktronic Sand Subs can appear in the Beach Trick "Feeding Frenzy", along with Shark Costume Zombies.
Its ability to dig underground is based on the Zombot Sharktronic Sub's ability to dive underwater in the second game.
Sharktronic Sand Sub is quite dangerous when it's about to pops out. Using Buttercup can stun it, preventing to bite her instantly and gives the player a chance to defeat it.
- Unlike his Plants vs. Zombies 2 and Plants vs. Zombies Heroes counterparts, it now has a red antenna instead of yellow.