There are no restrictions on the number of pension schemes that you can belong to. However, there are limits on the total contributions across all schemes each year that you can get tax relief on. If you’ve more than one job, each of your employers will check whether you’re an eligible jobholder (or type 1 member) for that employment. If you are, then you’ll be auto-enrolled into that employer’s workplace pension scheme, but you may decide to opt out.
If you want to opt out, you’ll need to opt out of EACH job you have.
If you’re a non-eligible jobholder or an entitled worker you may ask to join that employer’s workplace pension scheme.
If you leave an employer, you may be able to combine the benefits held under each scheme by transferring one pension pot in to another.