How do I lock the ring box when proposing outdoors?

You don't lock the ring box. You secure the ring, and you make the box almost irrelevant. Most lockable ring boxes are a gimmick. The tiny combination dial or key latch looks reassuring in a product photo, but it doesn't solve the actual outdoor risks: dropping the box into snow, water, sand, or a crevasse, or having it slip out of a pocket when you kneel.

What I'd actually do

I've handled a few of these so-called lockable boxes. The locks are usually pot metal, the hinges are weak, and the mechanism adds size without improving closure. A stiff snap or a zippered leather pouch does more than a three-digit dial ever will. If you want real security, put the ring in a small hard-sided case, like a Pelican 1010 or an equivalent knockoff. They run about $20 and close with a positive latch that won't open on its own. Then put that case in an interior zippered jacket pocket. Not a pants pocket. Not an open chest pocket on a flannel. An interior zippered pocket on a shell or a coat.

• Use a box with a firm snap or a leather zip case. Velvet boxes with a weak magnetic catch are the worst outdoor option.
• Put the ring box or case into a small dry bag if you're near water, snow, or sand. A 4-liter roll-top dry bag costs under $15 and clips to a belt loop or a backpack strap.
• Clip the dry bag or case to your clothing with a small carabiner or a retractable key loop. The tether is the real lock.
• Carry the ring in an interior zippered pocket designed for valuables. If your jacket doesn't have one, use a front hip pocket on fitted pants and keep your hand near it.
• Once you reach the spot, take the ring out and hold it in your closed palm. The box is now just props.

Last October a client named Daniel planned a kayak proposal at dawn and insisted on a floating ring box with a tiny combination lock. I told him the lock would be the thing that failed. He bought it anyway. Morning of, 38 degrees, his hands were shaking, and he couldn't turn the dial. He'd had the sense to move the ring into a small cloth pouch in his dry bag the night before. He proposed with the ring in his palm. The floating lockable box is still in his closet, unused.

If you truly want a locking container, don't use a ring box. Use a small lockable hard case or a leather pouch with a zipper that takes a tiny luggage padlock through the zipper pulls. That works. It also looks less precious, which is an advantage when you're on a trail and don't want to advertise that you're carrying an engagement ring.

The thing nobody tells you about proposing outdoors is that you'll probably forget everything you rehearsed, and the only detail that actually matters is having one physical location for the ring that never changes and one tether to your body.