Your cylinder can be refilled either in one of the dive stores around Zurich, or from a few unmanned filling stations. Those new to Switzerland may have already discovered that they won't be able to obtain fills from dive stores on Sundays - they are all closed. Therefore the option of using some of the unmanned filling stations is particulaly attractive for those who wish to enjoy diving when they have free time, which can often be a Sunday.

All dive stores will provide air refills during their opening hours, and most good dive stores will also provide nitrox refills to those possessing a nitrox certification. To see a list of dive stores in the Zurich region, see the corresponding information item in this section.

For those wishing to obtain refills outside of the store opening hours, an automated filling station is very convenient. One of the more popular facilities is at WZT, Tiefenbrunnen. To use this filling station you will require an electronic "U-key", which has to be pre-paid in advance, and a large key deposit (usually CHF 50) must also be paid. After all, these plastic keys must be very valuable.

The key system works for any filling station that is linked to the Luftverbund, which has members all over Switzerland. This allows you a certain degree of flexibility. However, before you are overwhelmed with the luxury of not having to fit around someone else's schedule you should be aware that your U-key can only be recharged in the dive store where you bought it. Therefore you should ensure that you get your U-key from a dive store close to you, and remember also that you will have to go there personally to recharge, during the opening hours of the store. There is no possibility to recharge from a machine, or via credit card. Once you have accepted this limitation, you are free to use your U-key anywhere in the Luftverbund. Prices vary between the members, but you will usually pay around CHF 3 per cubic meter (1000 litres). Therefore filling a 12 litre cylinder staring with 50 bar to 200 bar will cost you around CHF 5.40 (1800 litres or 1.8m3).

Of course there are other possibilities to obtain refills outside of store opening hours apart from the Luftverbund. If you are at WZT and drive back towards to Zurich, after a couple of minutes you'll see the parking area for Zurihorn and the casino on your left. Park here and you'll find a small building about ten meters from the bottom of the car park. On the side of the building is a small wall-mounted cabinet. Open the door and you'll find a filling station inside. Inserting a five franc coin will operate the compressor for a fixed time. This is a very slow method of filling your tank, but convenient if you don't have a U-key.

Some dive stores operate external filling stations without a U-key, in this case you usually pay on a yearly basis and can fill as often as you like. One such store is Blue Divers in Schwamendingen.

For divers with a nitrox certification Tauchbasis Inauen provides 24-hour EAN32 fills for a fixed yearly charge, regardless of how much nitrox you use. The location of the nitrox facility is right next to the external filling station at WZT.