Yes, and it is the ordinary arrangement rather than an unusual one. Nothing in the rules restricts how many pension schemes you belong to, and holding a workplace pension for the employer contribution while running a SIPP for everything else is what a great many people do. The constraint sits on contributions, not on accounts.
One allowance, however many pensions
GOV.UK states that the annual allowance is the most you can save in your pension pots in a tax year before you have to pay tax, that it is 60,000 pounds, and that it applies to all of your private pensions if you have more than one. It counts the total paid into a defined contribution scheme by you or anyone else, employer contributions included. So two pensions do not give two allowances; they give one shared allowance and two sets of charges.
Keep the workplace scheme for the employer money
The reason to hold both rather than to choose is that the employer contribution exists only inside the workplace scheme. Leaving it to concentrate everything in a SIPP forfeits that money, and no charge saving replaces it. The usual pattern is therefore to contribute at least enough to the workplace scheme to attract the full employer contribution, and to direct anything above that to the SIPP where the investment choice is wider.
Watch the earnings limit and the flexible access trap
Two further limits catch people holding both. HMRC limits tax relief on your own contributions to 100 percent of your earnings in the year, which binds tightly for a director on a small salary even though company contributions are treated differently. And once you have flexibly accessed any pension, a lower money purchase annual allowance replaces the standard one across all of them, so drawing an income from one pension restricts what you can still pay into the other.
Consolidating is a separate question
Holding both while contributing is straightforward. Moving an existing workplace pension into a SIPP is a different decision, because older schemes can carry guaranteed annuity rates, protected tax free cash or exit penalties that are lost on transfer. This site does not advise on transfers, which is a regulated activity, and where a recommendation is needed the enquiry goes to an authorised firm.
Other questions people ask
Is there any restriction on holding both?
None. GOV.UK confirms the annual allowance applies across all your private pensions where you have more than one, which presupposes that holding several is normal. The restriction is on total contributions, not on the number of schemes.
How much can go into both together?
The annual allowance is 60,000 pounds a year across every pension, counting contributions from you, your employer and anyone else. Separately, relief on your own contributions is capped at 100 percent of your earnings in the year.
Will my employer pay into my SIPP instead?
Some will and many will not, since they are only obliged to contribute to the scheme they have chosen. For a company director, the company can pay directly into a SIPP, which is a common arrangement and is treated as an employer contribution.
Does drawing from one pension affect the other?
Yes. Flexibly accessing any pension triggers the money purchase annual allowance, a lower contribution limit that then applies across all of your pensions, including ones you have not touched.