How can I check if my AirPods are fake?

Here is how to Identify your AirPods - Apple Support — see what shows up, there. This checks the innards.

Also check the serial number with Apple: https://checkcoverage.apple.com/ though those can be cloned.

Purchasing from reputable and established vendors, and avoiding deals too-good-to-be-true, too.

Find the serial number on the AirPods case. This will be located on the under-side of the lid, in the left cup, and on the bottom of the right earpiece. Once you see your Apple serial number, go to checkcoverage.apple.com and type the number in there. If they are authentic, the search will find that they are Apple AirPods. This will not work with any fake serial number.

Hmmm, the best way to ensure that any products you buy are genuine and not counterfeit are to buy from an authorized dealer or direct from the manufacturer. That you're asking the question suggests that maybe you received yours as a gift or acquired them some other way. Here's a decent page on how to tell: https://legitcheck.app/guides/apple/airpods-fake-vs-real/#Step_1_Check_whether_the_serial_number_matches_Apples_official_records. There are lots of other type pages on the first page of a Google search on this, but they all generally focus first on the serial number and then on some other identifying markings. Unfortunately, its really the serial number that is the tell, as counterfeiters get better and better each year at emulating markings of other kinds. Good luck!

--JDee