diff --git a/2024/src/aoc/days/day3.py b/2024/src/aoc/days/day3.py
new file mode 100644
index 0000000..16c835d
--- /dev/null
+++ b/2024/src/aoc/days/day3.py
@@ -0,0 +1,25 @@
+import re
+
+from . import SeparateRunner
+
+
+class DayRunner(SeparateRunner):
+    @classmethod
+    def part1(cls, data: str) -> int:
+        return sum(int(a) * int(b) for a, b in re.findall(r"mul\((\d+),(\d+)\)", data))
+
+    @classmethod
+    def part2(cls, data: str) -> int:
+        do = True
+        total = 0
+        for op, a, b in re.findall(r"(don't\(\)|do\(\)|mul\((\d+),(\d+)\))", data):
+            match op:
+                case "do()":
+                    do = True
+                case "don't()":
+                    do = False
+                case _:
+                    if do:
+                        total += int(a) * int(b)
+
+        return total
diff --git a/2024/tests/test_day3.py b/2024/tests/test_day3.py
new file mode 100644
index 0000000..427093c
--- /dev/null
+++ b/2024/tests/test_day3.py
@@ -0,0 +1,12 @@
+from aoc.days.day3 import DayRunner
+
+SAMPLE_1 = "xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))"
+SAMPLE_2 = "xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))"
+
+
+def test_sample_part1() -> None:
+    assert DayRunner.part1(SAMPLE_1) == 161
+
+
+def test_sample_part2() -> None:
+    assert DayRunner.part2(SAMPLE_2) == 48