Until the October Revolution, the official time in Moscow corresponded to GMT+02:30:17 (according to the longitude of the Astronomical Observatory of Moscow State University). In 1919 the Council of People's Commissars of the RSFSR introduced the system of time zones in the country, and Moscow was assigned to the second administrative time zone, equal to GMT+02:00. Other zones east of the 37.5° meridian to Arkhangelsk, Vologda, Yaroslavl, Kostroma, Ivanovo, Vladimir, Ryazan, Tula, Lipetsk, Voronezh and Rostov-on-Don were also included in the second belt.

In accordance with the 16 June 1930 Decree of the Council of People's Commissars, the Decree Time was introduced by adding one hour to the time in each time zone of the USSR, so that Moscow Time became three hours ahead of Universal Time.^{[citation needed]}

Until 2011, during the winter, between the last Sunday of October and the last Sunday of March, Moscow Standard Time (MSK, МСК) was three hours ahead of UTC, or UTC+03:00. In the summer, Moscow Time shifted forward an additional hour ahead of Moscow Standard Time to become Moscow Summer Time (MSD), making it UTC+04:00.

In 2011, the Russian government proclaimed that daylight saving time would be observed all year round, thus effectively displacing standard time — claiming health concerns attributed to the annual shift to-and-fro DST.^[1] On 27 March 2011, Muscovites set their clocks forward for a final time, effectively observing MSD, or UTC+04:00, permanently.

On 29 March 2014, after the annexation of Crimea by the Russian Federation, the Republic of Crimea and the city of Sevastopol — two federal subjects established by Russia on the Crimean Peninsula — switched their time to MSK on 30 March 2014 (from UTC+02:00 with DST to UTC+04:00 with permanent DST).

On 1 July 2014, the State Duma passed a bill partially repealing the 2011 change, removing permanent DST and putting Moscow Time from 26 October 2014 on permanent UTC+03:00 and thus back to standard time.

Most of the European part of Russia (west of the Ural Mountains) uses Moscow Time. Kaliningrad Oblast uses Kaliningrad Time (UTC+02:00). Samara Oblast and Udmurtia use Samara time (UTC+04:00) and Perm Krai, Bashkortostan and Orenburg Oblast use Yekaterinburg time (UTC+05:00). Since 2014, Moscow Time has been observed in Crimea after it was annexed and in Russian-occupied territories of Ukraine, including after their declared annexation in 2022.^[3]

Moscow Time was also formerly used in European parts of the then-USSR:

• Estonia, in 1940–1941 and 1944-1989
• Latvia, in 1940–1941 and 1944-1989
• Lithuania, in 1940–1941 and 1944-1989
• Kaliningrad Oblast (Russia), in 1946–1989
• Moldova, in 1944-1990
• Ukraine, in 1930–1941 and 1943-1990
• Samara Oblast (Russia), in 1989–1991 and again from 2010–2011
• Belarus, in 1930–1941, 1944-1991 and again from 2014
• Crimea, in 1930–1941, 1944-1990, 1994-1997 and again from 2014

Moscow Summer Time (UTC+04:00) was first applied in 1981 and was used:

• until 1989 in Estonia, Kaliningrad Oblast, Latvia and Lithuania
• until 1990 in Moldova and Ukraine
• until 1991 in Belarus
• between 1989 and 1991 and in 2010 in Samara Oblast.

In 1922–1930 and 1991–1992, Moscow observed Eastern European Time (UTC+02:00). Daylight saving time (UTC+03:00) was observed in the summer of 1991, and the city and region reverted to UTC+03:00 by the summer of 1992.

The time in Moscow has been as follows (the following list of DST usage may not be accurate):^[4]

Since political, in addition to purely geographical, criteria are used in drawing time zones, they do not precisely adhere to meridian lines. The "purely geographical" MSK (UTC+03:00) time zone would consist of the band between meridians 37°30' E and 52°30' E. However, there are European locales that despite lying in an area with a "physical" UTC+03:00 time, are in another time zone; likewise, there are European areas that have gone for UTC+03:00, even though their "physical" time zone is different. Following is a list of such anomalies:

Areas west of 37°30' E ("physical" UTC+02:00) that use UTC+03:00

• The entirety of Belarus with 23°10' E as the westernmost point where UTC+3 has been used since 2011, thus aligning with MSK since 2014 (see also Minsk Time)
• Western Russia, including Saint Petersburg, half of Moscow and Crimea

Areas between 52°30' E and 67°30' E ("physical" UTC+04:00) that use UTC+03:00

• Russia, including most of Franz Josef Land, Yuzhny Island, most of Severny Island with an exception to the very east, and some parts of the Russian mainland (Komi Republic, Nenets Autonomous Okrug, east of Kirov Oblast and Tatarstan)

Areas east of 67°30' E ("physical" UTC+05:00) that use UTC+03:00

• The very east of Severny Island in Russia with 69°2' E as the easternmost point where MSK is used

Areas that use UTC+02:00

• Eastern parts of Ukraine

Areas that use UTC+04:00

• Georgia with an exception of Abkhazia and South Ossetia
• Armenia
• Azerbaijan
• The Russian Oblasts of Astrakhan, Samara, Saratov and Ulyanovsk with an exception to the very east
• Western half of the Russian Republic of Udmurtia

Areas that use UTC+05:00

• The western tip of Perm Krai in Russia, and the western parts of the Orenburg Oblast in Russia

• East Africa Time, also in UTC+03:00
• Time in Russia

• Current time in Moscow^{[dead link]}