Original Channel (1996–1997)

Sky 2 originally was launched on 1 September 1996 and served as a sister channel to Sky 1 in the evening, timesharing with Fox Kids. The channel was introduced to offer an expanded range of general entertainment programming, with Sky 2 airing a mixture of programmes already carried on Sky 1 along with programmes exclusive to the channel. Sky 2 however was not as successful as Sky had hoped, and would close nearly a year later without any notice on 31 August 1997. The channel was then replaced by the UK's version of National Geographic.

Sky One Mix/Sky Mix (2002–2005)

On 7 October 2002, Sky announced that they would launch their first digital channel in over a decade; Sky One Mix, functioning as Sky One's sister channel and catch-up service.^[1] The channel's launch was announced for 9 December on 13 November 2002^[2] and launched on Sky Digital that day.

The channel, initially broadcasting from noon to midnight, offered up the best of Sky One's programmes, as well as a dedicated children's block called "Animix", which broadcast from 3:30pm every weekday. ^[3] The channel used a logo and presentation design similar to that used by Sky One at the time, but with a yellow and black theme as opposed to the orange and white used by Sky One at the time.

Initially exclusive to Sky Digital, the channel was added to NTL at the end of July 2003 as part of a two-year contract extension between BSkyB and NTL.^[4]

On 21 September 2004, to coincide with Sky One's new look, Sky One Mix was rebranded as simply Sky Mix, although it kept with Sky One's previous branding as before and kept the same idents without the mention of the word "One".

Sky Two (2005–2008)

Sky2 logo used from 2008 to 2011

On 18 July 2005, rumours circulated that Sky was planning to extend the Sky One brand by rebranding Sky Mix as Sky Two, and launching a Sky Three as well.^[5] The channel rebranded effectively to Sky Two in November of that year and began using Kaktus Films' animated idents in line with those introduced on Sky One the prior year.

On Thursday 1 March 2007, Sky Two, alongside other non-premium Sky networks, were removed from Virgin Media following a contract dispute between Virgin Media and BSkyB caused by the expiry of their carriage agreement and their inability to reach a new deal.^[6] When Sky Two was removed, Virgin Media renamed the slot on the EPG as "Old Sky Two Try Living", before it was removed completely.

In February 2008, Sky Two began utilising the same short-lived range of idents that its sister channels used, except using a "Green" range of graphics.

Sky2 (2008–2020)

On 31 August 2008, the channel adopted a revised branding of Sky2, when Sky's entertainment channels relaunched with numeric names and shared branding elements, utilising blue solids (Sky1), green liquids (Sky2) and pink particles (Sky3).^[7]

On 13 November 2008, following the agreement of a new deal between BSkyB and Virgin Media, Sky2 along with Sky's other non-premium channels returned to Virgin Media's television service.

From 10 May to 9 August 2010, Sky conducted an experimental revision of service, under which Sky2 ceased to run its own full-time programme schedule, and instead predominantly operated a one-hour timeshift of programming on Sky1.^[8] Sky2 would, however, retain standalone branding. A Sky spokesperson said: "We are experimenting with different channel schedules to bring maximum value to our customers." Some programmes were excluded from the timeshift device and replaced by alternate content on Sky2 during this period; shows which weren't shown on the time-delay included the premiere of Sky1's Terry Pratchett's Going Postal, the station's adaptation of the author's Discworld novel. Also not seen on a timeshift basis was the final ever episode of Lost, which was aired at 5 am, as a simultaneous being broadcast with the US transmission. The last episodes of 24 (which Sky showed as a two-part finale) also weren't shown an hour later on Sky2. The non-timeshifted programming would often be found an alternative slot on Sky2 (Terry Pratchett's Going Postal would be shown later in the week), essentially making Sky2 a 4seven-style 'time shuffle' channel during these periods. The timeshift trial concluded on 9 August 2010, with Sky2 reverting to its previous scheduling pattern.

On 1 February 2011, Sky refreshed the presentation on many of its channels. Sky2's new idents would follow along the same themes as Sky One's, but the action is in close-up, featuring a small metal '2' icon (in contrast to Sky1's giant '1' symbol). Sky1 would later switch to programme-themed idents, whilst Sky2 largely continued to use the 2011 sequences; in April 2016, when Sky1 got new animated identity sequences, Sky2 received a revised version of its 2011 films, with a larger Sky2 logo caption appearing at the end of the sequence, and the backing music changed to that previously used by the Sky1 version of the films.

Whilst it initially enjoyed a prominent position on the Sky guide close to Sky1, Sky2 had since 2011 progressively been moved down the programme guide on the Sky satellite platform to make room for other services. In February 2011, to make way for the relaunched Sky Living, Sky2 moved to channel 129, previously home to Syfy. On 21 February 2012, it moved up to 121, previously owned by Sky Living +1. In 2015, with the re-combination of Sky Arts into a single channel and its move up the grid, Sky2 moved back to 129. And in summer 2017, the relaunch of Sky Sports into genre-based channels saw the move of Sky Sports Mix into the entertainment guide, resulting in the relocation of other services including Sky Two. On 1 May 2018, Sky Two moved up to channel 123 as part of another reshuffling by Sky. It replaced ITV Encore, which closed on the same day. On 22 October 2018, the channel moved down to 151, swapping places with E!. On 1 October 2019, the channel moved down to 170 following the closure of Real Lives and launch of Sky Crime, and moved again to 168 on 19 November 2019 following the closure of YourTV.

On 9 October 2017, the branding and presentation on Sky's entertainment channels was revised again; as part of this the names Sky One and Sky Two were reintroduced nine years after the switch to numerals. Sky Two dropped its previous filmed idents in favour of using an animated sting featuring the new channel logo.^[9]

Whereas Sky One had been available in HD since the launch of Sky HD in 2006, Sky Two has always been exclusively available in standard definition.

Sky Replay (2020–present)

On 27 August 2020, Sky Two was rebranded as Sky Replay and moved to Sky channel 145 as a result, while its previous owner, Sky Sports Mix, moved to channel 416.^[10]

On 8 November 2022, Sky Replay swapped channel numbers with Challenge.