- For the international version of this level, see Pirate Seas - Day 25.
Pirate Seas - Ultimate Challenge is the twenty-fifth and the last level of Pirate Seas in the Chinese version of Plants vs. Zombies 2. It is a boss battle against the Zombot Plank Walker. The player has to collect all stars in previous levels in order to unlock this level. When this level is finished for the first time, the player earns coins, a Magical Chest and three stars.
The Zombot Plank Walker acts the same way as it does in the international version. That being said, the player this time can set up a defense before the fight, rather than fight the Zombot with given plants. 4000 sun is given, which is more than enough to defeat this. One thing to worry about is the Imp rain, which can cause some devastation to your defenses if the back is not guarded well. The Zombot can also can do a charge attack, so save some Plant Food or bring Power Lily along just in case. However, this level can be done in mere seconds if Level 4 plants are used, as the amount of health the Zombot Plank Walker has does not scale, and is always preset. This means using Level 4 plants can do tons of damage and defeat the Zombot Plank Walker very quickly. There is no hard mode to this level either.
- A strategy like those in previous Last Stand levels will work for this level. Using Level 4 plants to deal tons of damage to the Zombot Plank Walker is recommended.
- Always stall the zombie with the highest level of threat such as Barrel Rollers, Gargantuars, and Imps because these are the only zombies that will wreck the entire row of your plant combos. As much as possible, keep two Plant Foods at disposal.
- Never use Plant Food on Kernel-pults to try and stop the charge attack. It has no effect.
- Watch out for the Imp rain, as the Imps are Level 2. Use Level 4 plants or Plant Food to counter them.
- When you know it is about to charge towards your lawn, simply stun it with plants that are fed with Plant Food or Level 4 plants even though this is also a good way to eliminate zombie hordes.
- This level used to have only level 2 zombies.