Candidates who have been selected by their party or have indicated they intend to run so far are:
- Siobhan Benita - Independent
- Sian Berry - Green Party
- George Galloway - Respect Party
- Lindsay Garrett - Something New Party
- Paul Godling - Britain First
- Zac Goldsmith - Conservative Party
- Sadiq Khan - Labour Party
- Caroline Pidgeon - Liberal Democrat Party
- Rosalind Readhead - Independent (Ban Private Cars in London)
- Upkar Singh Rai - National Liberal Party
- Sandi Toksvig - Women's Equality Party
- Peter Whittle - United Kingdom Independence Party (UKIP)
- Yanek Zylinski - Independent (anti-UKIP)
Early campaigning began with the process of major parties selecting candidates, after the 2015 General Election. The first party candidate to be announced was Lindsey Garrett of the Something New party on 18 May, though most parties declared candidates in September. Early issues that were highlighted by multiple candidates include:
Rising costs of house buying and renting, alongside a shortage in social housing. Candidates such as Sian Berry are promising a rent cap, while both Zac Goldsmith of the Conservatives and Sadiq Kahn of Labour have argued for increased home building. Caroline Pidgeon is in favour of increased use of rent-to-buy loans and George Galloway has pledged to use Compulsory Purchased Orders to obtain empty homes for social housing.
Public transport costs and the ongoing development of London's transport infrastructure, including Crossrail will also be major issues. Conservative candidate Zac Goldsmith has made infrastructure a major part of his campaign, emphasizing increased rail and cycling capacity. Sadiq Kahn of Labour has promised to freeze bus and rail fares, while both Sian Berry and Caroline Pidgeon have supported cycling.
Expansion of London's airports. Kahn, Goldsmith, Pidgeon and Berry were all signatories to a letter vowing to do use all possible powers to try and stop of expansion at Heathrow, though Kahn has argued instead for the expansion of Gatwick. UKIP candidate Peter Whittle has also come out against Heathrow's expansion Independent candidate Siobhan Benita is the only candidate to have stated support for a further runway at Heathrow.
Crime and police reform. Both Kahn and Goldsmith have highlighted rising hate crimes, with Goldsmith and Caroline Pidgeon both also pledging to tackle violent and knife crime. Sian Berry has pledged to increase resources into London's Violence Against Women and Girls Strategy. While George Galloway has pledged to crack down on white collar crime, and reform the Metropolitan Police.
The Environment is a key issue for several of the candidates, including Sian Berry of the Green Party, Zac Goldsmith of the Conservative Party and Ban Private Cars in London candidate Rosalind Readhead are long standing environmental campaigners. Berry has put sustainability at the centre of her campaign, while Goldsmith sees environmentalism more closely tied to economic growth. Khan has also pledged to put environmental concerns at the heart of his campaign, while Caroline Pidgeon is noted as a campaigner for green forms of transport.