diff --git a/src/entity/object/PrimedTNT.php b/src/entity/object/PrimedTNT.php
index ec621adfb80..8355a9404c2 100644
--- a/src/entity/object/PrimedTNT.php
+++ b/src/entity/object/PrimedTNT.php
@@ -118,7 +118,6 @@ public function explode() : void{
 		$ev = new EntityPreExplodeEvent($this, 4);
 		$ev->call();
 		if(!$ev->isCancelled()){
-			//TODO: deal with underwater TNT (underwater TNT treats water as if it has a blast resistance of 0)
 			$explosion = new Explosion(Position::fromObject($this->location->add(0, $this->size->getHeight() / 2, 0), $this->getWorld()), $ev->getRadius(), $this);
 			if($ev->isBlockBreaking()){
 				$explosion->explodeA();
diff --git a/src/world/Explosion.php b/src/world/Explosion.php
index 601f9109e27..401089aff7f 100644
--- a/src/world/Explosion.php
+++ b/src/world/Explosion.php
@@ -27,7 +27,9 @@
 use pocketmine\block\RuntimeBlockStateRegistry;
 use pocketmine\block\TNT;
 use pocketmine\block\VanillaBlocks;
+use pocketmine\block\Water;
 use pocketmine\entity\Entity;
+use pocketmine\entity\object\PrimedTNT;
 use pocketmine\event\entity\EntityDamageByBlockEvent;
 use pocketmine\event\entity\EntityDamageByEntityEvent;
 use pocketmine\event\entity\EntityDamageEvent;
@@ -82,6 +84,11 @@ public function explodeA() : bool{
 			return false;
 		}
 
+		$worksUnderwater = false;
+		if($this->what instanceof PrimedTNT || $this->what instanceof TNT){
+			$worksUnderwater = $this->what->worksUnderwater();
+		}
+
 		$blockFactory = RuntimeBlockStateRegistry::getInstance();
 
 		$mRays = $this->rays - 1;
@@ -120,12 +127,18 @@ public function explodeA() : bool{
 							$state = $subChunk->getBlockStateId($vBlockX & SubChunk::COORD_MASK, $vBlockY & SubChunk::COORD_MASK, $vBlockZ & SubChunk::COORD_MASK);
 
 							$blastResistance = $blockFactory->blastResistance[$state] ?? 0;
+							if($worksUnderwater && $blockFactory->fromStateId($state) instanceof Water){
+								$blastResistance = 0;
+							}
 							if($blastResistance >= 0){
 								$blastForce -= ($blastResistance / 5 + 0.3) * $this->stepLen;
 								if($blastForce > 0){
 									if(!isset($this->affectedBlocks[World::blockHash($vBlockX, $vBlockY, $vBlockZ)])){
 										$_block = $this->world->getBlockAt($vBlockX, $vBlockY, $vBlockZ, true, false);
 										foreach($_block->getAffectedBlocks() as $_affectedBlock){
+											if($_affectedBlock instanceof Water){
+												continue;
+											}
 											$_affectedBlockPos = $_affectedBlock->getPosition();
 											$this->affectedBlocks[World::blockHash($_affectedBlockPos->x, $_affectedBlockPos->y, $_affectedBlockPos->z)] = $_affectedBlock;
 										}