There are two Aspire Lounges at the Zurich International Airport besides a few other lounges. I visited the Aspire Lounge in the Satellite-Building with the E-Gates for Non-Schengen flights. The Schengen-Area is an area compromising 26 European states that have officially abolished passport and all other types of border control at their mutual borders. I was departing Zurich on an American Airlines flight to JFK.
After check-in and security, I headed towards the E-Gates and head to pass through passport control and taking the automated people mover to the satellite building. Once at the main level follow the signs for the lounge, which is located above Gate E45. The lounge is easy to find and you can take either the elevator or stairs. From the upper level, you have access to a few lounges like the Emirates lounge. As American Airlines doesn’t have its own lounge at ZRH, they have an agreement with the Aspire Lounge that Business and First Class customers can enter the lounge. I am sure American Airlines is not the only international carrier which has this kind of agreement. Just check with your airline and see if they offer any lounges in ZRH.
Besides that, you can access the lounge if you purchase a day-pass for CHF35.- or have a Priority Pass membership.