diff --git a/README.md b/README.md
index 2a4d4a1..b3e4f92 100644
--- a/README.md
+++ b/README.md
@@ -7,4 +7,4 @@ I started learning Haskell very recently, and I just learned this year that Adve
 |02 |★ ★  |07 |★ ★  |12 |★    |17 |★ ★  |22 |★    |
 |03 |★ ★  |08 |★ ★  |13 |★ ★  |18 |★ ★  |23 |★    |
 |04 |★ ★  |09 |★ ★  |14 |★ ★  |19 |★    |24 |★    |
-|05 |★ ★  |10 |★ ★  |15 |★    |20 |     |25 |     |
+|05 |★ ★  |10 |★ ★  |15 |★    |20 |     |25 |★    |
diff --git a/adventofcode2024.cabal b/adventofcode2024.cabal
index 093a979..a92b31f 100644
--- a/adventofcode2024.cabal
+++ b/adventofcode2024.cabal
@@ -60,4 +60,5 @@ executable adventofcode2024
     Day22
     Day23
     Day24
+    Day25
     Graph
diff --git a/src/Day25.hs b/src/Day25.hs
new file mode 100644
index 0000000..14e4f64
--- /dev/null
+++ b/src/Day25.hs
@@ -0,0 +1,32 @@
+{-# OPTIONS_GHC -Wno-x-partial #-}
+
+module Day25 (day25_1) where
+
+import Control.Monad (guard)
+import Data.List (transpose)
+import Data.List.Split (splitOn)
+
+parseSchematics :: [String] -> [Int]
+parseSchematics s =
+  let s' = transpose . init $ tail s
+   in map (length . filter (== '#')) s'
+
+keyLockCombinations :: [[Int]] -> [[Int]] -> [[Int]]
+keyLockCombinations keys locks = do
+  key <- keys
+  lock <- locks
+
+  guard $ all (< 6) $ zipWith (+) key lock
+
+  return $ zipWith (+) key lock
+
+day25_1 :: IO ()
+day25_1 = do
+  contents <- lines <$> readFile "input/day25.txt"
+  let schematics = splitOn [""] contents
+      locks = map parseSchematics $ filter (\x -> head x == "#####" && last x == ".....") schematics
+      keys = map parseSchematics $ filter (\x -> head x == "....." && last x == "#####") schematics
+  putStrLn $
+    "Day 25, Puzzle 1 solution: "
+      ++ show (length $ keyLockCombinations keys locks)
+  print . length $ keyLockCombinations keys locks
diff --git a/src/Main.hs b/src/Main.hs
index 1641a3e..5951fc1 100644
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -22,6 +22,7 @@ import Day19 (day19_1)
 import Day22 (day22_1)
 import Day23 (day23_1)
 import Day24 (day24_1)
+import Day25 (day25_1)
 import System.Environment (getArgs)
 
 main :: IO ()
@@ -110,6 +111,7 @@ main = do
     "22" : "1" : _ -> day22_1
     "23" : "1" : _ -> day23_1
     "24" : "1" : _ -> day24_1
+    "25" : "1" : _ -> day25_1
     "all" : _ -> do
       day01_1
       day01_2
@@ -148,4 +150,5 @@ main = do
       day22_1
       day23_1
       day24_1
+      day25_1
     _ -> error "Not implemented"