While most European countries have had a system of long distance buses for a long time, intercity bus travel was virtually nonexistent in Germany until 2012. Things have changed rapidly since then and intercity buses are now a relatively cheap way to get to a wide range of German and a handful of international destinations.
Long distance bus services which competed with the railways were prohibited in Germany from 1934 until the market was liberalised in 2013. The main exceptions were services to and from Berlin and international lines with few stops in Germany, mainly to central and eastern European countries.
Prices are often lower than competing train services, because of fierce competition and because buses don't pay for using roads, whereas trains (even those operated by the state-owned Deutsche Bahn) have to pay for using tracks.
Buses are usually slower than even regional train services, unless the connection by bus is more direct. There are three main reasons for this:
While connecting services with a change of buses are possible, most companies don't guarantee connections. Delays due to traffic are especially common during holidays and on weekends.
As with many forms of infrastructure, the west of Germany is better served than the east, where most companies focus on routes to/from Berlin and major Baltic Sea Coast destinations while mid-sized cities have few or no connections. On the other hand the Berlin - Dresden route is one of the best served in the market with fierce competition driving down prices, mostly due to it being part of the Berlin - Prague route, which is also served by international operators to whom the German domestic market is incidental at best.
The bus companies (which usually means Flixbus) mainly compete with trains and cars rather than with other bus companies.
Generally speaking the buses are reasonably new and safe, but legroom and seat pitch is often unsatisfactory for large people. Most bus companies sell snacks and drinks on board (or make stops at places where you can buy food), but you should still consider bringing your own as the selection is very limited. Although Wi-Fi is often promised, it is not available in all buses. The internet connection is provided via a normal cellphone signal so bandwidth and access (especially on a full bus) may be limited.
While most companies will transport bicycles for a fee, capacity is usually very limited (hardly more than three or four per bus) and it requires advance notice. Taking a foldable bicycle or putting a bicycle in a bag and declare it normal luggage is less feasible on buses than on trains as there is little space in the bus and the luggage compartments and excess baggage will almost certainly incur a surcharge. It might work out cheaper and more comfortable to take an IC or regional train (most ICE trains do not transport bicycles unless in the ways mentioned above, when they are deemed "luggage").
Like long distance trains and most flights in Germany, prices for buses are cheapest when booked well in advance online. Some companies operate their own ticket offices (sometimes integrated into other shops like newspaper shops) at some bus stations. However, ticket offices don't usually sell tickets for competing companies, so you might end up paying more than you would have online.
You can buy tickets directly from the driver prior to boarding, however expect to pay up to ten times the (advertised) lowest possible rate. Also, you are not allowed to board a bus if all seats are taken, as standing is illegal on long distance buses in Germany.
Most companies also sell tickets through tour operators. However, prices will be higher than the rates online, as there will be a premium for the vendor or the personal service included in the price.
Unlike for trains, there are no discounts for frequent travellers. Unlike in aviation, connecting services are never cheaper than any given part of them.
In 2018, Flixbus controlled around 90% of the domestic market. Prices have been slowly increasing. Routes with heavy competition or smaller players on the market still offer some bargains, but clearly the days of ultra-cheap fares are over. Nevertheless, unless the train connection is much inferior in other terms (more changes, longer travel time), a bus ticket bought on the same day will usually be cheaper than a train ticket for the same trip, if the train ticket is not discounted. In 2019 Blablabus challenged the Flixbus monopoly with low prices and Pinkbus introduced fixed rates for buses.
Deutsche Bahn has introduced a few special offers specifically to compete with bus operators and some aggregator websites even list Deutsche Bahn, so check before you buy a ticket. Most aggregators don't figure in BahnCard discounts where they are applicable. It can be easier to find tickets for slower-but-cheaper trains on bus aggregator websites than it is on DB's own website. Enabling "local transport only" on DB's website excludes IC/EC and ICE displaying only regional trains, which are often slower and cheaper.
In general, cancellations are relatively easy but only possible before the scheduled departure of the bus.
The market has seen many rapid changes with liberalization which first affected the domestic market but later forced some of the older international companies to withdraw from the market.
The market for domestic services consolidated a lot in late 2016 with Flixbus taking over almost all domestic competition and some of the others folding. Ever since, prices have been slowly but surely increasing, but are still below those for most comparable train tickets and flights. Buses still do not pay any toll for roads, but some cities are trying to charge for the use of bus station facilities. However, some companies in the past chose to only serve stations with no or low access fees. The Flixbus monopoly was seriously challenged in 2019 by Blablabus only for the Covid-19 pandemic to hit in 2020 and upend the market yet again.
Most buses don't operate from dedicated stations. Instead, they typically stop near central (train) stations. Some cities have a central bus station ZOB (Zentraler Omnibus Bahnhof), often centrally located. If you don't know the bus stop, check your ticket: it usually includes an address and a small map of the stop.
Some companies serve more than one station in a city, especially if the city is very big (e.g. Berlin), has more than one major train station (e.g. Dresden) or has a major international airport (e.g. Frankfurt). Be sure to be at the right station and for connecting services check whether the stop where your connection departs from is the same where your bus arrives. If not, figure out how to get from one to the other and how much time that takes. Unless you are going by light rail, subway or tram, it would be wise to plan some extra time for traffic congestion.
Many cities discussed constructing bus stations once it became clear that intercity bus travel was here to stay. Cost concerns mean that not all that much has been built as of 2018. Where bus stations do exist, they usually have few shopping options, and they tend to be just as overpriced as convenience stores at gas stations. Some stations have been relocated because of conflict between bus operators and cities, often as a result of congestion. Some stations are closer to the airport than the city centre, so check where your bus stops: actually getting downtown may involve a lengthy (and sometimes costly) trip on another mode of transport.
Intercity buses in France - modelled after the German system and some players are or have been active in both markets.