Big Wave Beach - Day 31 is the thirty-first level of Big Wave Beach in Plants vs. Zombies 2. It is a Locked and Loaded level. The tideline in this level is located before the first column, which means that the tide will rise, and water will cover the entire lawn at one point during the level. After completing this level, the player receives a money bag.
- This level is incredibly difficult to defeat without the use of Power Ups and lawn mowers, since the player is only given Homing Thistle as an offensive plant. Though hordes of zombies are delayed in this level compared to other levels, Homing Thistle often cannot keep up with the zombies despite this.
- The player must use Sun Bean as a source of sun production, otherwise they will be too starved of sun to plant anything. This can be really difficult with Octo Zombies and Fisherman Zombies.
- Since Homing Thistle is glitched, the level will be harder as Homing Thistle won't be able to keep up with the Zombies.
- The small number next to the zombie icon means that zombie will always appear in that lane, with 1 being the topmost lane and 5 being the bottommost one.
|Waves||Non-dynamic zombies||Ambush zombies||Note(s)|
|2||None||Water reaches 7th column|
|4||None||Water reaches 6th column; 100% Plant Food|
|5||None||600%/7 Plant Food|
|6||None||Water reaches 4th column|
|8||5 1 5||None||First flag; water reaches 5th column|
|9||None||100% Plant Food|
|10||None||Water reaches 3rd column; 400%/7 Plant Food|
|12||1 5||None||Water reaches 2nd column; 500%/7 Plant Food|
|13||None||100% Plant Food|
|14||1 1 2 3 2 3 2||None||Water reaches 1st column|
|16||1 3 5 4||None||Final flag; water covers whole lawn|
- Tangle Kelp can be used to take down the first zombies, while enough sun is collected to plant Homing Thistles. Subsequently, it is especially useful for killing stronger and more dangerous zombies, namely Buckethead Zombies, Octo Zombies, and Fisherman Zombies.
- As no sun-producing plants are given, using Sun Bean on Conehead Zombies and Buckethead Zombies is necessary.
- Wall-nuts are not needed for Homing Thistles to attack Snorkel Zombies.
- Only one Deep Sea Gargantuar appears, during the final wave.
- Use Plant Food on Homing Thistles to deal with octopi, the Deep Sea Gargantuar and any rogue Octo Zombies and Fishermen Zombies.
- You can also find that there are only four Fishermen Zombies appearing in this battle, so you can plant Homing Thistles in the lane where none of them appear.
- Boost the Sun Bean if you have enough gems or if it is in your Zen Garden.
- Make sure you plant a Lily Pad before you plant the plant, in case it gets washed by the tide.
- Day 31 is the sixth and final level where the tide goes all the way to the player's house (first column), the others being Day 7, Day 13, Day 18, Day 27, and Day 29 of Big Wave Beach.