Push it up against the backsplash. You will find it more beneficial to have the extra counter space in front of sink vs behind the sink.

It depends a bit how you use the sink -- is this in the master, for example? I would find 5" of counter in front of the sink quite uncomfortable to use for many activities, especially if you, say, rinse your head or otherwise need to get close. It might matter less in a powder room, although I suspect that it will feel unnatural to reach your hands that for for a standard faucet.

Forgot to mention.

I am remodeling the vanity area for both a master bath with dual sink vanitiy and a powder room with a single sink.

There are definitely certain advantages to either placement. I appreciate all the comments/opinions.

whatever you do - make sure you can get behind it with a hand and a paper towel or rag to clean it - less than 2.5" seems to beg for hard to clean space.

Not back against the wall. Doing that will not stop water getting back there, but will block you from cleaning it up. Another reason is your back. When a sink is back from the front of the counter, it means leaning a bit forward to reach it. That may be no problem for you now, but get lower back pain and you will want the sink pulled forward. There is a reason that kitchens get so many farmhouse sinks! Lastly, if you ever need a wheelchair or a rollator walker, you need the sink right up front. People of all ages can have an injury that makes them semi-mobile for a period of time.

If it's back against the backsplash, it's only an extra 2-3 inches in the front. I could be wrong, but it doesn't seem like it would make a big difference in reaching a little further back. Also, I would be caulking around the top of the sink so that no water gets in between the sink and backsplash.

I’d have it tight against the backsplash and well-grouted.

If you have any back issues, having to reach forward, even a few more inches, can make a big difference in placing stress on the back when using a sink daily. I always want my sinks as far forward as possible.

I can say that the extra inch or two added in front of my kitchen sink to make space for a tilt-out drawer tires my back every single day. Oh, to have realized that would happen! 2-3 inches would make me use a different bathroom. But I'm not tall.

Can you find the same sink but deeper?? I would not push it back - all those inches in front are too much.

Good luck!!

Alicia, when you have already planned on a vessel sink, you have a counter that is lower to account for the sink’s height. Putting in an undermount sink at that point means having a sink too low to be comfortable. Bathroom sink counters used to be lower than kitchen counters. Only in the past several years have they come up to 35-36” “kitchen” height. With my back, reaching down that low first thing in the morning when I was stiff was not possible. I used to have to lean to the side even to reach the faucets in the morning. Lower back degeneration gets a lot of us as we age. Planning ahead to prevent problems is a good idea.

Yes, Nancy I realize that. That’s why I prefaced my post with “ If it’s not too late”. The photos from the OP are just inspiration photos, not their own bathroom. OP doesn’t say that the vanity has been installed. When we renovated our ensuite we had a taller vanity, custom built, so we could have a drop in sink at a comfortable height.

Has anyone used "Schluter" to trim a vessel sink where it sits on the countertop. I think that product may help for cleanup and clean lines. But, do they make it the correct size for this application (I know that there are different proviles (maybe convex or concave) "Schluter" is a brand name, there are many other brands. I believe that it is a metal trim that is used instead of a "Jolly" (long thin piece of ceramic tile that would finish the edge ur tile application.

Thank you everyone. I decided to center it rather than against the backsplash. I will post pictures once all installed.