The short answer is: make the furniture harder to take than it is worth, and don’t rely on just one method. I’d approach it in layers.
Start with the right furniture for the location. In busy, well-lit areas, you can use lighter movable seating; in quiet or high-risk spots, choose heavier benches, fixed tables, and designs with fewer loose parts. If furniture must stay put, anchor it properly—stainless or galvanized expansion bolts into concrete, tamper-resistant fasteners, and locking pins rather than ordinary screws. Where drilling isn’t possible, use weighted bases or ballasted planters, and make sure the weight can’t be easily removed.
For tables and chairs that need some flexibility, use security chains or cable locks, but keep them neat and hidden so the space still looks welcoming. Anti-theft fasteners, thread-locking adhesive, and welded or one-piece frames also help. I’d also mark furniture with asset tags, engraving, or discreet GPS trackers for high-value pieces; clearly marked items are less attractive to casual thieves and easier to recover.
Placement matters as much as hardware. Put seating where people can see it, near lighting, active frontages, or cameras, and avoid dark corners that give thieves time and privacy. Good lighting and regular patrols or community reporting can be just as useful as a lock. Keep maintenance in the loop, too: check anchors and fasteners regularly, replace damaged parts quickly, and remove abandoned or broken furniture before it becomes an easy target.
Finally, talk to your supplier or manufacturer about security options from the start. The best setup is usually a mix of anchored or weighted furniture, tamper-resistant fixings, smart placement, and a community that notices and reports problems.