If you're dealing with persistent theft or vandalism of your outdoor trash bins, you need a robust locking solution that deters even determined thieves. The most secure approach combines multiple layers of protection rather than relying on a single mechanism.
For maximum security in high-theft areas, I'd recommend a heavy-duty shrouded shackle padlock combined with a reinforced hasp. Look for a laminated steel padlock with a hardened steel shackle at least 10mm thick - these are extremely difficult to cut with bolt cutters. The shroud protects the locking mechanism from tampering while preventing access to the shackle. Pair this with a heavy-duty hasp that's properly installed using security screws that can't be easily removed.
Consider combination locks if you need multiple people to access the bin without key management issues. Modern combination locks with weather-resistant coatings work well outdoors. For permanent installations, integrated locking systems built specifically for trash enclosures provide excellent security as they're designed to resist prying and tampering.
Remember that the mounting hardware is just as important as the lock itself - use security screws or bolts that can't be easily unscrewed. Position the locking mechanism in a way that makes it difficult to access with tools. In extreme cases, you might consider a fully enclosed trash container with built-in locking system, though this represents a more significant investment.
No lock is completely theft-proof, but using these heavy-duty options significantly increases the effort required to breach your trash storage, which is often enough to deter thieves who typically look for easy targets. Regularly inspect your locking system for signs of tampering and consider adding motion-sensor lighting to increase security further.