Switzerland is a surprisingly good place for cycling, largely due to its good cycling network. Swiss bike efforts are often stylized under the heading "Veloland Schweiz" which is Swiss standard German for "bike country Switzerland".
For standard bicycles and E-bikes capped at 25km/hr a helmet is not required. A helmet is required when riding a 45km/hr E-bike.
Lights are required in low light conditions and in tunnels for all bikes. All E-bikes are required to have front and rear lights attached to the bike, with the front light on at all times.
According to Swiss traffic law, a bicycle is considered as a road vehicle. As a cyclist you have to follow the same rules, and rights, as any other traffic member, such as cars and lorries. Therefore make sure you know the extensive Swiss traffic rules and traffic signs.
Riding on footpaths is a complicated issue. The current law on the matter states that bikes should not be ridden on roads that were not intended for, but that pre-dates mountain biking by several decades. In some cases the rules are clear: in canton Appenzell Innerhoden it is forbidden to ride on footpaths outside of a few approved routes, whereas in Graubünden you are allowed to ride on any footpath unless it is explicitly signed otherwise. For most of the country it is something of a grey area and riding on the footpaths is generally accepted so long as it does not cause conflict with others on the path. Always ride carefully and give pedestrians right of way.
Bikes can be transported on most trains and some buses.
A day ticket for your bike to go any distance can be bought for 14 CHF, or for shorter trips below that cost a half-price ‘childrens’ ticket will cover the bike. A reservation is required during the summer season on inter-city trains and most bus services (check the information on connections).
The amount of space for bikes is very variable. Some trains have a whole carriage for bikes, whilst some inter-city trains only have 6 crampt spaces for the whole train.
In addition to self-loading bikes the SBB also offers a bike shipping service (20 CHF for bikes, 30 CHF for E-bikes) where you can drop the bike off at one station then pick the bike up from another station two days later.
Downhill mountain biking is becoming increasingly common with many ski resorts offering day passes on lifts and building groomed trails. Graubünden (Lenzerheide, Flims/Laax) and Valais (Crans-Montana, Verbier) are the two main regions.
Cross country mountain biking is a huge sport in Switzerland. This is unsurprising to anyone who has watched a world cup race before and seen half of the top ten seized by Swiss riders. The main reason for Swiss excellence in the sport is probably the amazing training area they have in their backyard. Thus Switzerland is an amazing place for everyone who likes mountain biking.
There are numerous options to find routes: Schweizmobil.ch includes routes varying from multiday tours going across the whole country to local loops (all of which are sign posted on the ground), local tourism websites will have numerous suggestions, and crowd-sourced websites such as Komoot are popular too. Another option is the Swiss Singletrail Map from Ride.ch which requires an annual subscription to access the digital map covering the entire country, or you can buy paper maps for certain regions.
There are mountain bike specific paths around some ski resorts, but most of the time you will be using public footpaths. Be respectful to other trail users and be prepared for a rocky/rooty ride on single trail sections.
The cycling infrastructure for everyday cycling varies between the cities. Basel, Winterthur and Berne are the champions which can almost compete with Dutch and Danish cities. In general the German-speaking regions are better for cycling than the French-speaking ones. There are many Swiss cities where you can rent bicycles if that is your means of traveling and you can even rent electric bicycles. During the summer it is quite common for cities to offer bicycle 'rental' for free!
A number of signposted cycling routes cross back and forth over the country, a list of routes and map can be found at schweizmobil.ch.
These routes are generally intended to be as scenic and avoid traffic as much as possible. The result is that they are often on gravel roads or poorly maintained farm roads, something that will be fine for touring bikes but rather uncomfortable for those on road bikes.
In addition to the cycling routes there are also skating routes which might appeal to families because they follow flatter and quieter routes, again see schweizmobil.ch for more information.
There is very little in the way of separated cycling infrastructure in Switzerland. Cycling routes will guide you onto quiet back/farm roads when possible, but in urban areas you will often be on roads with only painted lines on the ground for protection from traffic. Drivers are generally very careful and considerate, but care should still be taken when riding around.
Petty theft is relatively uncommon in Switzerland but it is still important to properly secure your bike when it is unattended – especially in cities.
A number of cites (for example Bern, Zürich, Basel) have tram tracks which can catch bike wheels if you approach them at a shallow angle.