0.5 down from street size (I'm normally a 10, so 9.5 in these) and it fits perfectly. Tried 9s but my feet were getting bruised too much and it hurt a lot. With 9.5s there are still minor marks on my toe knuckles but it's pretty reasonable and very comfortable compared to other shoes.

I've been climbing in a pair of Oasis for about a year.Pros:-- Supremely comfortable, without sacrificing much performance. I can easily wear them for a long pitch or two before I feel discomfort.-- Super sensitive, and capable in smearing;-- but also fairly precise and capable in edging, as well. That is, a pretty capable shoe all-around.-- Heel is a pretty good fit for me (low-volume heel) and hooks are good.-- Toe rubber is sufficient but not more.Cons:-- The velcro strap system on these shoes is horrible. They wear out quickly, won't stay closed, and flap around in the breeze. Just awful.-- The shoes use the old formulation of the Vibram XS Grip (not XS Grip 2); would hope to see the new one on such a high-end shoe.-- The midsole of the shoe is soft, ... MoreI've been climbing in a pair of Oasis for about a year.Pros:-- Supremely comfortable, without sacrificing much performance. I can easily wear them for a long pitch or two before I feel discomfort.-- Super sensitive, and capable in smearing;-- but also fairly precise and capable in edging, as well. That is, a pretty capable shoe all-around.-- Heel is a pretty good fit for me (low-volume heel) and hooks are good.-- Toe rubber is sufficient but not more.Cons:-- The velcro strap system on these shoes is horrible. They wear out quickly, won't stay closed, and flap around in the breeze. Just awful.-- The shoes use the old formulation of the Vibram XS Grip (not XS Grip 2); would hope to see the new one on such a high-end shoe.-- The midsole of the shoe is soft, meaning it will lose its downturn vs. a shoe like the Solution. But that's usually the trade off for a highly sensitive shoe.-- Durability in the upper is an issue; the rand is delaminating from the upper on both my shoes with only very typical and almost gentle use. But, the soles and the edge-rand seam are holding up very well.Fit:I think the fit is a narrow fit for a men's shoe, but slightly wide for a women's shoe. I found it comparable to and just wider than La Sportiva men's. You will want to size down---I typically wear 39-39.5 in most shoes, but needed a 38.5 in the Oasi. (I wear a 38.5 in the Solutions, and a 40-40.5 in the Katana Lace.) It's hard to say but I feel like mine stretched about 1/4-1/2 a size; a bit more than the Solutions.Overall:A comfortable but highly capable shoe. There are definitely some flaws, but they don't seriously detract from the shoe's total performance. Best for sport climbing indoors or out, since they can handle a variety of terrain, and be worn for long periods without pain.

I don't really know how to describe all that's great about this shoe. What I think of first is how natural it feels on foot while climbing. To keep it simple, this is a shoe that I more or less forget that I'm wearing, because they are that comfortable (if the narrow last fits your foot that is). Combining that element of zero distraction, with the fact that these have a super precise pointed toe, enough downturn for steeper routes/boulders and a stiff enough toe for decent edging -- you get my go-to shoe.I have had to pick a con, it's that I don't love these for heel hooking. I feel like the Tenaya could improve the heel fit on their shoes a bit. It is good enough where it doesn't detract enough from my overall experience.I find Tenaya's sizing advice to be ... MoreI don't really know how to describe all that's great about this shoe. What I think of first is how natural it feels on foot while climbing. To keep it simple, this is a shoe that I more or less forget that I'm wearing, because they are that comfortable (if the narrow last fits your foot that is). Combining that element of zero distraction, with the fact that these have a super precise pointed toe, enough downturn for steeper routes/boulders and a stiff enough toe for decent edging -- you get my go-to shoe.I have had to pick a con, it's that I don't love these for heel hooking. I feel like the Tenaya could improve the heel fit on their shoes a bit. It is good enough where it doesn't detract enough from my overall experience.I find Tenaya's sizing advice to be pretty spot on. They recommend about 1 full size down from street shoe. My street shoe is 11.5/12 and I wear these in an 11 and a 10.5 and they are both great. If you really wanted to size down more, you probably could, but don't be fooled by the comfort of the shoe! I don't think it's entirely necessary to size down so much in these.I would also recommend the Oasi LV, Tarifa and Mundaka (Mundakas fit a bit wider up front).