Hello Isabel,

In my experience you would normally be able to take your bike without problems. The lower levels are rarely crowded on the Geneva-Nyon line.

Hi why dont you go with the bike ? :)) from geneva i did it today it took me 1hour and half from geneva ,but if you are not willing to ,take car you have to buy a ticket for the bike or a carte journaliere for the bike ,bikes in trains are payable in swizertland 

Of course, a foldable bike is ideal for bringing on public transport. In that yous, I don't think you need a ticket for it.

Alternatively, leave a bike in Geneva overnight. There are locked bike parkings by the stations.

Thanks for the advice everyone! I'll be needing to go Nyon-Geneva and Geneva - Nyon with the bike everyday, so cycling all the way or leaving the bike in Geneva isn't really an option. 

I didn't realise you had to pay for the bike, good to know!

Why not leaving a bike in Geneva?A second-hand bike used only for going o the office doesn't cost much.

I have a bike parked at the office, only used for going around town. My real bike, I keep at home.

So ask for a passport velo you will pay 240 chf per year for the bike or if you buy a special bag for the bike you don't have to pay for the bike 

https://www.sbb.ch/en/travelcards-and-tickets/tickets-for-switzerland/bike-tickets.html

https://www.sbb.ch/en/timetable/travel-advice/bicycles/take-your-bike-with-you/tranzbag.html