The twist-and-lock mechanism on a Pixel Watch is well designed but not obvious. Most people who find it difficult are pulling when they should be turning.
Here is the method.
Removing a band
Hold the watch face down in one hand, with the half of the band you want to remove pointing away from you.
Find the small release button next to the opening where the band enters the case. Press and hold it.
With the button held, rotate the band gently away from the case, as though you were swinging it outward rather than pulling it straight off. Once it clears the catch it slides out of the channel easily.
If it will not move, you are almost certainly pulling rather than twisting. The band cannot come straight out; the geometry does not allow it.
Fitting a new band
Line the connector up with the opening at a slight angle, matching the angle it came out at. Slide it into the channel, then rotate it back flush with the case until it clicks.
You should feel the catch engage. Give the band a gentle tug afterwards to confirm.
The two halves are different
The top and bottom halves of a Pixel Watch band are not interchangeable with each other. They are shaped to fit their own side of the case.
If one half simply will not seat no matter what angle you try, swap the two and try again. This is the single most common cause of a band that feels faulty out of the box.
If the mechanism feels stiff
New bands are often tighter than the one you have been wearing for a year. That usually eases after a few swaps.
Grime in the channel is the other cause, particularly if you swim or train in the watch. A cotton bud and a little warm water clears it. Let it dry fully before fitting the band.
What not to do is apply serious force. The catch is a small mechanism, and the case is the expensive part of this equation.
How often can you swap?
As often as you like. The mechanism is designed for it, and there is no wear penalty to changing daily.
The practical case for two bands is that no single material is good at everything. Silicone handles the gym, the shower and sleep tracking. Leather and metal look right everywhere else and should stay out of water.
After every change, check the fit
A new band sits differently to the old one even when it looks similar. The watch should sit snug against the skin about a finger's width above the wrist bone.
Too loose and the heart-rate sensor picks up motion instead of pulse, which shows as readings that lag behind your effort. Too tight restricts blood flow and skews them the other way. It is worth ten seconds of adjustment rather than assuming the old setting carries over.
One thing that will not work
A standard watch strap. The Pixel Watch has no lugs and no spring bars, so a 20mm band has nothing to attach to, whatever the listing claims.
Shop Google Pixel Watch bands, or read our full Pixel Watch band guide.