Slitherlink Online Free — 3,000 Puzzles and a Daily Challenge

Draw lines around the numbers to make one closed loop. No sign-up — play right in your browser.

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Select a puzzle to start playing

Click: draw / erase · Right-click or Ctrl+click: mark ×

Today's puzzle

Size

Difficulty

Three rules, that's all

A minute to learn, a lifetime to master.

Connect the dots
Tap (or click) between two neighbouring dots to draw a line. Tap again for ×, once more to clear.
Numbers count lines
A number says how many of the cell's four sides are part of the loop. Empty cells can have any number.
Make one loop
The lines must form a single closed loop with no branches and no crossings.

Example puzzle and its answer

Slitherlinks is the definitive free online platform for Slitherlink puzzles — the loop-forming logic puzzle originally published by Nikoli in 1989 and recognized as one of the most elegant constraint-satisfaction puzzles in recreational mathematics. Known internationally as Fences, Loop the Loop, Takegaki (囲い), 数回 (Chinese), スリザーリンク (Japanese), and 슬리더링크 (Korean), Slitherlink has a dedicated solving community spanning over 30 countries.

What is Slitherlink? Slitherlink is a pure-logic puzzle where you draw a single closed loop on a rectangular grid. Each numbered cell indicates exactly how many of its four edges belong to the loop. According to combinatorial analysis, even a modest 7×7 grid can encode billions of potential loop configurations — yet every well-formed Slitherlink puzzle has exactly one valid solution, discoverable through deductive reasoning alone without any guessing.

3,400 Puzzles
5 Grid Sizes
3 Difficulty Levels
Daily Challenge
Mobile Friendly
100% Free

Frequently Asked Questions

What is Slitherlink and how do I play?

Slitherlink is a logic puzzle where you connect dots to form a single closed loop. Numbers on the grid indicate how many of the four surrounding edges belong to the loop. Use these clues to deduce which edges must be part of the loop and which must be empty.

Basic rules: The loop must be continuous (no breaks), cannot cross itself, cannot branch off, and must satisfy all number clues. Start with corners and 0/3 clues as they have the fewest possibilities.

Is Slitherlink really free? Do I need an account?

Yes, Slitherlinks is 100% free with no registration required. You can play any puzzle from our library of 3,000 challenges without creating an account.

Creating a free account is optional but recommended if you want to save your progress, compete on leaderboards, track personal statistics, and earn achievements.

What grid sizes and difficulty levels are available?

We offer five grid sizes: 5×5 (2-5 min), 7×7 (5-10 min), 10×10 (10-20 min), 12×12 (15-30 min), and 15×15 (20-40 min). Each size includes Easy, Medium, and Difficult variants, giving you 15 total categories.

How do I get better at solving Slitherlink puzzles?

Start with 0s and 3s — they have only one valid configuration. Look at corners which are heavily constrained. Use diagonal patterns, avoid creating loops too early, and mark impossible edges with right-click.

Can I play Slitherlink on mobile devices?

Absolutely! Slitherlinks is fully optimized for mobile phones and tablets. Our responsive design automatically adjusts the game board size, with intuitive touch controls: tap to draw lines, long-press to mark empty edges.

Can I print Slitherlink puzzles?

Yes! Visit our Print Puzzles page to generate printable Slitherlink puzzles. Choose your preferred grid size and difficulty, download a single-page A5 or A4 PDF, and print it whenever you like — perfect for commutes, flights, or screen-free time.

Slitherlink Online Free — 3,000 Puzzles and a Daily Challenge

Three rules, that's all

Connect the dots

Numbers count lines

Make one loop

Frequently Asked Questions