As enticing as it is to play through The Legend of Zelda: Breath of the Wild with Link wearing almost nothing, you'll quickly find that enemies can kill you much more easily this way. Just like in other video games, armor is pretty helpful. A Bokoblin's club won't hurt as much if you're protected by Hyrule's finest steel plates.
So where can you get the best armor in Breath of the Wild? That's a complicated question, as different high-end armor sets provide different bonuses. In practice, you're going to switch to different outfits based on different situations instead of relying on one set for everything.
Here are a few of the best armor sets you should have in your inventory: the best I've found in Breath of the Wild, where to get them and when they should be equipped.
Zelda: Breath of the Wild's best armor: Hylian set
The Hylian hood, tunic and trousers can be acquired very early in the game, from the clothing shops in Kakariko and Hateno Villages. Aside from looking pretty cool, they're pretty easy to upgrade at Great Fairy Fountains and they provide decent armor for general combat situations. After you upgrade each piece of the set a couple of times, they offer a total of 28 armor, which got me through Hyrule Castle and the final boss fights with little trouble.
Zelda: Breath of the Wild's best armor: Climbing set
If you've found yourself frustrated by the game's slow, stamina-draining climbing, this is the set for you. Collecting all three pieces of the set will make Link climb incredibly fast and use less stamina in the process. It's pretty invaluable for exploration.
VG247 has a helpful guide to finding the three pieces of the set, which are all in different shrines in the eastern portion of the map. You'll need to brave the snowy peaks of Mount Lanayru to get two of them, so bring cold-resistance gear, food or elixirs for your journey. The only downside is that the set makes Link look like one of those jerks who do slacklining in the park.
Zelda: Breath of the Wild's best armor: Snowquill gear for cold resistance
The best outfit for cold resistance is the Snowquill get-up that you can buy in Rito Village, located in the northwest section of the map. Simply put, you can survive in the game's coldest environments by equipping this outfit. It'll cost you a combined 2,150 rupees, which isn't all that much money if you've done a dungeon or two before heading up there.
Zelda: Breath of the Wild's best armor: Flamebreaker gear for fire resistance
The Vah Rudania dungeon in Death Mountain will be pretty much impossible to finish without a way to ward off the extreme volcanic heat. That's where the Flamebreaker armor set comes in.
On the path to Goron City, you'll find a guy wearing goofy looking heavy armor with a side quest to collect 10 fireproof lizards. If you do this for him, he'll give you one piece of the Flamebreaker armor, which should be enough to at least endure the heat during your time at Death Mountain. Gosu Noob has a guide to the side quest, which is pretty easy to complete.
Alternatively, you can buy the set for a whopping 3,200 rupees at Goron City's clothing shop.
Zelda: Breath of the Wild's best armor: Guardian set for guardian resistance
If those terrifying spider-like guardians are killing you with their powerful beam attacks, this set will help you out. You can buy it from the Akkala Ancient Tech Lab for 6,000 rupees and a smattering of ancient tech parts harvested from guardians. This set will make the guardians' beam attacks do significantly less damage. It will also make guardian shields and weapons more powerful when you wield them.
Zelda: Breath of the Wild's best armor: Sand Boots and Snow Boots
If you're tired of moving really slowly in sand or snow, head out to Gerudo Town and find a guy named Bozai running around outside the town. As long as you're dressed in your Gerudo disguise, he'll give you a side quest with his sand boots as a reward. In order to complete the side quest, he'll give you snow boots, as you'll need to trudge through the Gerudo Highlands up north. (Polygon has a comprehensive guide to the side quest.)
The twist is that once he gives you the sand boots, he'll take back the snow boots. Talk to him again to get another side quest with the snow boots as a reward (Polygon also has a guide for this one). Neither of them is too difficult as long as you're OK with climbing. Both of these boots make exploration much less tedious in desert and snowy climates.
Zelda: Breath of the Wild's best armor: Outfit of the Wild
Apparently, the ultimate armor set (as long as you're willing to put in tons of time and effort) is the Wild set. You get this one for finding and completing all 120 shrines in the world. This set makes the beam attack from the Master Sword more powerful, but if you upgrade it at Great Fairy Fountains, it apparently has great defensive prowess as well.
Unfortunately, I can't independently verify this. I have the set but haven't upgraded it because the requisite materials are more difficult to come by than other armor sets. This thread in the GameFAQs forum claims it has 88 total defense when fully upgraded, but I haven't done that yet. Still, given how difficult the set is to acquire and then upgrade, it would make sense for its final stats to be bonkers. (Do you have the Wild set? Tell us about it at firstname.lastname@example.org.)
More Zelda: Breath of the Wild tips, tricks and guides
Find out all there is to know about Zelda: Breath of the Wild, including what to expect from the Wii U version, how to preserve your items, how to beat bosses like the Stone Talus, Lynel, the Guardians and the Hinox, the best recipes for Link and how to take on the game's shrines. You'll also want to find out where all the great fairies and available stables are in the game, how to use amiibo with your version of Zelda and how to increase your health, stamina and weapon slots.