Public transit in San Diego County will run with reduced service on Christmas — but the Metropolitan Transit System is offering a promotion that lets bus and trolley passengers bring a guest who rides for free on the holiday.

Both MTS and the North County Transit District will operate Thursday on a Sunday schedule, with less frequent trips throughout the day and some services not operating at all.

But riders can take advantage of MTS’ Friends Ride Free promotion on Christmas Day, which lets every adult fare-paying passenger to bring a guest without paying a second fare. MTS also ran the promotion on Thanksgiving.

On Thursday, expect trolleys to run every 30 minutes. Rapid Express Routes 280 and 290 and Rural Routes 888, 891, 892 and 894 won’t be running.

In North County, the NCTD+ and Coaster Connection won’t operate. And MTS Access passengers must call ahead to arrange their transportation on Christmas.

Holiday travelers can get directly to and from the airport, as usual, using Route 992 from Santa Fe Depot or the San Diego Airport Flyer shuttle bus from the Old Town Transit Center.