iPhone 13 and iPhone 13 Pro are dual-SIM smartphones and you can have multiple eSIM phone numbers active at the same time.

You Can Use 2 eSIM Phone Numbers in Dual-SIM Mode on iPhone 13 and iPhone 13 Pro

The iPhone went dual-SIM with the iPhone XS and support for eSIM has been there for a long time. But this year, Apple is turning the heat up with eSIM. Rather than having a physical nano-SIM + eSIM configuration for dual-SIM support, you can use two eSIM phone numbers at the same time. In short, you can go all eSIM with the iPhone for dual-SIM mode and it will work like magic.

Keep in mind that your carrier should support eSIM in order to use it with your iPhone 13 or iPhone 13 Pro. If support is not there then this feature is basically useless.

Straight from Apple's website:

If you're a huge fan of the iPhone and love dual-SIM, then this smartphone really makes things better. But keep one thing in mind, you can only have two phone lines active at the same time. Either regular SIM + eSIM or eSIM + eSIM. If you were thinking that you can use the phone in a tri-SIM configuration then you need to dial your hopes down. Way down.

While you are here, check out the following:

iPhone 13 and iPhone 13 mini Are Official: Features 6-Core A15 Bionic, Custom OLED Display, Smaller Notch, MoreiPhone 13 Pro, iPhone 13 Pro Max Feature 50 Percent Faster Graphics, 120Hz ProMotion Display, Fresh Blue Color, More