https://techcrunch.com/2021/04/15/you-can-now-pay-for-bart-using-an-iphone-or-apple-watch/

Good news, Bay Area! Apple Pay now works with Clipper cards.

That means you can now use an iPhone or Apple Watch to pay for BART. Or Muni. Or Caltrain. Or the Ferry! Or (almost) any other transit-related thing you’d otherwise use the plastic Clipper card for.