Can I simultaneously connect two pairs of AirPods to my Apple Watch?
No this isn’t possible and is a limitation with Bluetooth.


  No. Unfortunately this is a limitation of the Bluetooth Standard.  Only one device of a specified type of connection can be used at a time through bluetooth.  So while you could use Airpods, an Apple watch and a Bt keyboard with an iPhone all at the same time you cannot use more than one of each at a time. 



https://discussions.apple.com/thread/8070777