Slitherlink are addictive loop-forming puzzles which were invented in Japan. Using pure logic and requiring no math to solve, these fascinating puzzles offer endless fun and intellectual entertainment to puzzle fans of all skills and ages.

Each puzzle consists of a rectangular lattice of dots with some clues in various places. The object is to connect the dots surrounding each clue so that the number of lines equals the value of the clue and the lines around all clues form one continuous loop with no crossings or branches. Empty squares may be surrounded by any number of lines.

The game features 2-finger tapping for quick zoom, auto complete clues setting and a link segment highlighting option to help to avoid creating separate loops.

For more fun, Conceptis Slitherlink includes a Weekly Bonus section providing an extra free puzzle each week.


• 90 free Classic Slitherlink puzzle samples
• 30 extra-large puzzles bonus for iPad only
• Extra bonus puzzle published free each week
• Multiple difficulty levels from very easy to extremely hard
• Puzzle library continuously updates with new content
• Manually selected, top quality puzzles
• Unique solution for each puzzle
• Hours of intellectual challenge and fun
• Sharpens logic and improves cognitive skills


• Concurrently playing and saving multiple puzzles
• Puzzle library sorting and hiding options
• Unlimited Undo and Redo
• Auto complete clues
• Highlight link segment
• Quick zoom using 2-finger tap
• Check puzzle
• Track puzzle solving times


Slitherlink have also become popular under other names such as Fences, Loop the Loop, Loopy, Suriza, Dotty Dilemma and Number Line. Similar to Sudoku, Kakuro and Hashi, the puzzles are solved using logic alone. All puzzles in this app are produced by Conceptis Ltd. - the leading supplier of logic puzzles to printed and electronic gaming media all over the world. On average, more than 20 million Conceptis puzzles are solved each day in newspapers, magazines, books and online as well as on smartphones and tablets across the world.

What's New

Version 3.5

This version improves performance and stability.

Ratings and Reviews

4.9 out of 5

62 Ratings

62 Ratings

This is one of my favourites


Conceptis has done it again. The thought that has gone into these puzzles is amazing. Do the free ones, then buy more. They're addictive.

Edited to add that I am getting better and better at these. They are currently my number one favourite Conceptis puzzle!

Love the logic games


This company makes the best games. They're not bright and splashy, but they don't need to be.
I do find myself wishing for a save button to make it easy to go back to a last known good moment in this game, but otherwise, it's a wonderful new style brain bending logic game. I give it full marks.

Fun brain teaser


It took me a bit to figure out how to play this. Now, I'm addicted! Great brain teaser. I like that the mobile version automatically puts in the x's when a path is not available. I would like to see that in the desktop version!


Conceptis Ltd.
15 MB
Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.
English, Japanese, Simplified Chinese
Age Rating
Rated 4+
© Conceptis Ltd.
In-App Purchases
  1. Medium Variety 1 $1.99
  2. Easy Variety 1 $1.99
  3. Hard Variety 1 $1.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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