Bus spotting is a pastime in which one seeks to see all buses in a particular fleet or those produced by a particular manufacturer. A person who engages in these activities is known as a bus spotter, bus fan (popular name in Hong Kong), bus nut (term popular in the UK) or bus enthusiast (although this term can also cover preservationists). Within the bus industry bus spotters are known as moquettes, from the material used to make the seat coverings. Like train and aircraft spotters, bus spotters spend much time outdoors with notepads, cameras or camcorders, monitoring bus routes.
Bus spotters are often uninterested in timetables and network quality, but they may be interested in new liveries, especially ad-hoc schemes to advertise particular products or events. Some may be so keen that they might track a vehicle through its life, knowing for example which fleet numbers it has carried with different owners and when mechanical parts or interior fittings were renewed. Bus spotting has never been as popular as train spotting in the UK, but enthusiasts can share the common term of "gricer"; however it has become popular in Hong Kong and bus societies have been formed there.
Bus spotters often enjoy riding buses and photographing them. Since bus spotting involves urban mass transit, it often goes hand in hand with metrophily. In New York, the two are often combined into "transit fan", a person who studies both bus and rail rapid transit, with the same diligence.
"Bus enthusiasts" do more than spotting buses: they are interested not just in vehicles, but also in the operation of bus companies and their fleets in general, and may include "bus preservationists" who buy, restore and run vintage vehicles. Bus enthusiasts may list or trace the whereabouts of surviving retired vehicles from a particular operator or collect scale models which may be customised to replicate particular vehicles or entire fleets. They may also collect uniforms and paraphernalia, such as conductors' ticket machines, in order to dress the part at events.
Bus spotter societies may organise "fan charters" by chartering a bus of choice and photographing it on different parts of the chosen route. Bus outings that take in a number of depots, with photographic tours of each, are also popular.
Bus spotters and enthusiasts are often found at major bus termini, bus depots, bus rallies and anywhere related to buses. There are a number of magazines aimed at bus enthusiasts and spotters, e.g. Buses Magazine.