diff --git a/inc/conf.h b/inc/conf.h
index f11e2b7..5e57133 100644
--- a/inc/conf.h
+++ b/inc/conf.h
@@ -10,8 +10,11 @@
 #define AIR_FRICTION        (AIR_ACCELERATION / MAX_WALK_SPEED)
 #define GROUND_FRICTION     (GROUND_ACCELERATION / MAX_WALK_SPEED)
 #define AIR_RESISTANCE      0.01f
+#define WATER_RESISTANCE    0.15f
 #define GRAVITY             0.3f
 #define JUMP_SPEED          -6.0f
+#define SWIM_SPEED          -1.6f
+#define SWIM_OUT_SPEED      -4.8f
 #define JUMP_BREAK          3
 #define JUMP_BUFFER         12
 #define JUMP_GRACE          6
diff --git a/inc/player.h b/inc/player.h
index 1cd8de2..ecb4f57 100644
--- a/inc/player.h
+++ b/inc/player.h
@@ -7,7 +7,7 @@ struct Player {
 	struct Vec pos, gravity;
 	struct VecF spd, rem;
 	enum AirState air_state;
-	int jump_buffer, jump_grace, burn, bouncing;
+	int jump_buffer, jump_grace, burn, bouncing, was_in_water;
 };
 
 void player_spawn(struct Player *);
diff --git a/inc/tile.h b/inc/tile.h
index 82c77fa..5f52320 100644
--- a/inc/tile.h
+++ b/inc/tile.h
@@ -13,6 +13,7 @@ enum Tile {
 	TILE_GRAV_U,
 	TILE_GRAV_R,
 	TILE_GRAV_L,
+	TILE_WATER,
 	TILE_COUNT,
 	TILE_OOB,
 };
diff --git a/inc/util.h b/inc/util.h
index 4b9f878..436b465 100644
--- a/inc/util.h
+++ b/inc/util.h
@@ -2,3 +2,5 @@
 
 int sign(int);
 float absf(float);
+float minf(float, float);
+float maxf(float, float);
diff --git a/res/tileset.png b/res/tileset.png
index 4e32e11..003c597 100644
Binary files a/res/tileset.png and b/res/tileset.png differ
diff --git a/src/player.c b/src/player.c
index ac4a817..2f90d24 100644
--- a/src/player.c
+++ b/src/player.c
@@ -26,6 +26,7 @@ player_spawn(struct Player *p)
 	p->jump_buffer = 0;
 	p->jump_grace = 0;
 	p->burn = 0;
+	p->was_in_water = 0;
 }
 
 void
@@ -33,6 +34,7 @@ player_update(struct Player *p)
 {
 	const int on_ground =
 	    collide_solid(p->pos.x + p->gravity.x, p->pos.y + p->gravity.y);
+	const int in_water = collide(p->pos.x, p->pos.y, TILE_WATER);
 	const int k_left = input_down(K_LEFT);
 	const int k_right = input_down(K_RIGHT);
 	// const int k_up = input_down(K_UP);
@@ -60,7 +62,7 @@ player_update(struct Player *p)
 	spd_x += dir_x * (on_ground ? GROUND_ACCELERATION : AIR_ACCELERATION);
 
 	/* air resistance & gravity */
-	spd_y *= (1 - AIR_RESISTANCE);
+	spd_y *= 1 - (in_water ? WATER_RESISTANCE : AIR_RESISTANCE);
 	spd_y +=
 	    (p->air_state == AS_BREAKING) ? (GRAVITY * JUMP_BREAK) : (GRAVITY);
 
@@ -96,6 +98,13 @@ player_update(struct Player *p)
 		p->jump_grace = 0;
 	}
 
+	/* swim */
+	if (k_jump && (p->was_in_water || in_water)) {
+		spd_y =
+		    minf(spd_y, (in_water) ? (SWIM_SPEED) : (SWIM_OUT_SPEED));
+		p->air_state = AS_RISING;
+	}
+
 	/* bounce */
 	if (collide(p->pos.x, p->pos.y, TILE_BOUNCER)) {
 		if (!p->bouncing) {
@@ -151,6 +160,8 @@ player_update(struct Player *p)
 		p->gravity.x = -1;
 		p->gravity.y = 0;
 	}
+
+	p->was_in_water = in_water;
 }
 
 void
diff --git a/src/util.c b/src/util.c
index 9088538..ec6b526 100644
--- a/src/util.c
+++ b/src/util.c
@@ -11,3 +11,15 @@ absf(float x)
 {
 	return x * (-1 + 2 * (x > 0));
 }
+
+float
+minf(float x, float y)
+{
+	return (x < y) ? (x) : (y);
+}
+
+float
+maxf(float x, float y)
+{
+	return (x > y) ? (x) : (y);
+}