This question has been in the back of my mind for ages while playing Violet. And it's always been annoying, because the only reason it had been unanswered for so long was because nobody knows how to count steps in this game (I'm not quite satisfied with the other answer). Let me preface that I still don't, nobody does, but let me get the important stuff out the way first.
- Jumping does not count as steps.
- Flying and gliding do not count as steps.
- Swimming does count as steps.
It's easy to get confused with jumping and flying/gliding because if you don't land perfectly still after flying/gliding/jumping, you roll forwards a little bit, but those are land steps.
If it matters, I tested jumping a while back, but I remember having an egg that was a "step" away from hatching. I was able to keep jumping up, moving forwards in the air, landing still, and repeating the process, travelling far. If I moved enough on the ground however, the egg began to hatch. The same applies for gliding.
For flying, I had an egg that was a few "steps" away from hatching. I ran a short distance, I hatched. I reset the game and tried again, but flying further than that distance and even more. I landed, went forwards a bit with Miraidon, and the egg didn't hatch. I needed to go even further to get the egg to hatch, meaning the time/distance I spent flying didn't count for steps.
Now, for how much steps count for. The real answer is that steps are impossibly hard to measure in this game, you can barely move forwards with a slight tap of the control stick, and your character will inch forwards. That, however, does not get the egg a step away from hatching to hatch. You can walk slowly, walk fast but not run, and be at a running speed. Because what counts as a step is so inconsistent, and dashing around on Miraidon/Koraidon on land is much faster and the best method for hatching eggs anyways, it's extremely pointless to worry about how much a step is in this game. However, I tried to figure that out anyways.
First, eggs are weird in this game. It's possible to get eggs to a point so close to hatching that a single movement input will make the egg hatch. However, if you save and reset the game, the egg will have a super short distance you need to travel to get it to hatch. It's a bit longer of a distance than the input, but it's still a short distance. This means that by continuously inching forwards in this short distance but not getting the egg to hatch, saving, resetting, and repeating the process, over time, you can travel farther than your original point without having the egg ever hatch. This short amount of distance you travel for the egg to hatch when you reload the game is what I will count as an "egg step", or the egg being a step away from hatching.
I tried two methods to measure this distance. The first method I tried a while back was trying to measure the amount of distance by comparing it to the amount of bricks I passed on the ground at the East side of Zapapico. This did not freaking work lmao, and was my first sign that figuring out steps in this game was not worth it.
My second method was trying to use the "Travel 500 yards" quest in Blueberry Academy, with the hopes that a regular step would = a yard. It did not. An egg step also did not = a full yard. But I wasn't ready to give up.
Another quirk in this game is that instead of eggs hatching one after another immediately, once one egg hatches, the next egg needs to complete another egg cycle in order to hatch. This means even if both eggs are a step away from hatch, once the topmost egg in the party hatches, the next one has to do another cycle, giving me a clear reference for how much an egg cycle was. According to Bulbapedia, an egg cycle in Scarlet and Violet is 128 steps.
With two eggs a step away from hatching, I let the first one hatch, before going back to Blueberry Academy (I flew to the same location each time) with the yards task at 0 yards covered. First, I ran until the egg hatched, and counting the steps, I traveled 64 yards in 30 steps. The first step might not have immediately been a running step, and it could have been more than 64 yards, not 64 yards exactly, but another test also had 30 steps while running, so those results are consistent.
Next, I tried a constant walking speed. While walking slowly (not inching or walking fast without running), I traveled 64 yards in 64 steps.
Next, I needed to see how many steps a yard was. 2 walking steps seemed to = 1 yard, and 1 running step also seemed to = 1 yard. Base on this, we're assuming 1 running step = 2 walking steps, for simplicity's sake. An egg step was less than 1 walking step, more than halfway, but not quite a full step.
So doing the math, since an egg cycle takes 128 steps to complete, 64 yards is the distance of an egg cycle, and it takes 64 walking steps to travel 64 yards, that means 1 egg cycle = 128 half walking steps. And since an egg hatches in over half a walking step, we'll round and say 1 egg step = 3/4 a walking step.
And of course, in the water, an egg step also doesn't get to 1 yard, so we can assume an egg step on land is the same distance as an egg step in the water.
You see how despite all this complicated mess to get an answer, the fact this still doesn't really tell us what a "step" is in this game means you probably shouldn't be worrying about this and just stick to dashing around on your Ride Pokemon for hatching eggs?
Yeah? I thought so.
I hope this freaking helped lmao.