You don’t need a tent, specifically, for backpacking but you do need some form of rain protection and/or insect protection in most climates when camping out along a trail. It can be a tent, hammock with a tarp, a waterproof bivy sack, a bug shelter, or some combination of these to provide the protection you need. You should also carry a shelter with you even if you plan to sleep in first-come-first-served lean-tos, cabins, hostels, or B&B’s along a well-established trail. You never know if there will be a spot for you when you arrive for the evening, so it’s best to hedge your bets.
Rain Protection
There are many forms of rain protection that backpackers can use including tents, tarps, or waterproof bivy sacks. All of these will keep you dry from rain falling from the sky, but you’ll probably want to augment a tarp with additional protection to keep you off the wet ground since they don’t have a built-in floor. This can as simple as a plastic sheet or a hammock, suspended between two trees, that keeps you off the ground entirely.

Why can’t you just sleep out in the rain? Water conducts heat away from your skin 25 times faster than air, which can lead to uncomfortable chilling and hypothermia, even in summer. Camping with some form of rain protection will keep you drier and warmer, so you can get some rest.
Insect Protection
Tents, hammocks with noseeum netting, bug bivies, and most bivy sacks have built-in noseeum netting to prevent mosquitos, black flies, and ticks from biting your while you sleep. If you’re sleeping on the ground in a tent or under a tarp, they also keep other harmful reptiles, spiders, or scorpions from getting too close to you.

If you don’t need rain protection, bug bivies and ultralight-style bivy sacks can be used in dry climates without a waterproof tarp for cowboy camping. They weigh less than a pound and there are some that are quite inexpensive.
See Also:
- Backpacking Bug Shelter Guide
- Backpacking Tarps Gear Guide
- Pyramid Tarp and Tent Guide
- Trekking Pole Tent Gear Gear Guide
- Hammock Tents Gear Guide
In my experience, you don’t usually need a tent (i.e., bug or rain shelter) for backpacking, but when you need that, you really need it! And it’s a long way to the trailhead if you don’t have it.
I think it really depends on your climate and the duration of your trip. For example, I would NEVER hike without some form of shelter, even if I only carry it for use in an emergency. Then again I hike where there are insects and wet weather.
Where I am it’s rare I’d say I strictly need a tent either. And this is spot on.
When you need it, you really need it!
I’m still not past the subconscious illusion that I’m more secure in my tent though either (ha!). And a zero percent chance of bugs while sleeping always feels good.
So even when I don’t need it, I use it. It’s just… Nice.