| 1 Jan, 2023 (Sun) | New Year's Day | Bank Holiday |
| 2 Jan, 2023 (Mon) | New Year's Day observed | Bank Holiday |
| 3 Jan, 2023 (Tue) | 2nd January (substitute day) | Local Bank Holiday |
| 5 Jan, 2023 (Thu) | Twelfth Night | Observance, Christian |
| 6 Jan, 2023 (Fri) | Epiphany | Observance, Christian |
| 7 Jan, 2023 (Sat) | Orthodox Christmas Day | Observance, Orthodox |
| 14 Jan, 2023 (Sat) | Orthodox New Year | Observance, Orthodox |
| 22 Jan, 2023 (Sun) | Lunar New Year | Observance |
| 25 Jan, 2023 (Wed) | Burns Night | Local Observation |
| 6 Feb, 2023 (Mon) | Tu B'Shevat (Arbor Day) | Jewish Holiday |
| 14 Feb, 2023 (Tue) | Valentine's Day | Observance |
| 18 Feb, 2023 (Sat) | Maha Shivaratri | Hindu Holiday |
| 18 Feb, 2023 (Sat) | Isra and Mi'raj | Muslim |
| 21 Feb, 2023 (Tue) | Carnival / Shrove Tuesday / Pancake Day | Observance, Christian |
| 22 Feb, 2023 (Wed) | Carnival / Ash Wednesday | Observance, Christian |
| 1 Mar, 2023 (Wed) | St. David's Day | Local Observation |
| 7 Mar, 2023 (Tue) | Purim | Jewish Holiday |
| 17 Mar, 2023 (Fri) | St Patrick's Day | Local Bank Holiday |
| 19 Mar, 2023 (Sun) | Mother's Day | Observance |
| 21 Mar, 2023 (Tue) | March Equinox | Season |
| 23 Mar, 2023 (Thu) | Ramadan Start | Muslim |
| 26 Mar, 2023 (Sun) | Daylight Saving Time starts | Clock change/Daylight Saving Time |
| 2 Apr, 2023 (Sun) | Palm Sunday | Observance, Christian |
| 6 Apr, 2023 (Thu) | Maundy Thursday | Observance, Christian |
| 6 Apr, 2023 (Thu) | First day of Passover | Jewish Holiday |
| 7 Apr, 2023 (Fri) | Good Friday | Bank Holiday |
| 8 Apr, 2023 (Sat) | Holy Saturday | Observance, Christian |
| 9 Apr, 2023 (Sun) | Easter Sunday | Observance, Christian |
| 10 Apr, 2023 (Mon) | Easter Monday | Local Observation |
| 10 Apr, 2023 (Mon) | Easter Monday | Common Local Holiday |
| 13 Apr, 2023 (Thu) | Last day of Passover | Jewish Holiday |
| 14 Apr, 2023 (Fri) | Orthodox Good Friday | Observance, Orthodox |
| 15 Apr, 2023 (Sat) | Orthodox Holy Saturday | Observance, Orthodox |
| 16 Apr, 2023 (Sun) | Orthodox Easter | Observance, Orthodox |
| 17 Apr, 2023 (Mon) | Laylatul Qadr (Night of Power) | Muslim |
| 17 Apr, 2023 (Mon) | Orthodox Easter Monday | Observance, Orthodox |
| 18 Apr, 2023 (Tue) | Yom HaShoah | Jewish Commemoration |
| 21 Apr, 2023 (Fri) | Eid ul Fitr | Muslim |
| 22 Apr, 2023 (Sat) | Eid ul Fitr | Muslim |
| 22 Apr, 2023 (Sat) | Stephen Lawrence Day | Observance |
| 23 Apr, 2023 (Sun) | St. George's Day | Observance, Christian |
| 23 Apr, 2023 (Sun) | St. George's Day | Observance |
| 23 Apr, 2023 (Sun) | Shakespeare Day | Observance |
| 26 Apr, 2023 (Wed) | Yom HaAtzmaut | Jewish Holiday |
| 1 May, 2023 (Mon) | Early May Bank Holiday | Bank Holiday |
| 6 May, 2023 (Sat) | The Coronation of King Charles III | Observance |
| 8 May, 2023 (Mon) | Bank Holiday for the Coronation of King Charles III | Bank Holiday |
| 9 May, 2023 (Tue) | Lag B'Omer | Jewish Holiday |
| 18 May, 2023 (Thu) | Ascension Day | Observance, Christian |
| 26 May, 2023 (Fri) | Shavuot | Jewish Holiday |
| 28 May, 2023 (Sun) | Pentecost | Observance, Christian |
| 29 May, 2023 (Mon) | Whit Monday | Observance, Christian |
| 29 May, 2023 (Mon) | Spring Bank Holiday | Bank Holiday |
| 4 Jun, 2023 (Sun) | Trinity Sunday | Observance, Christian |
| 8 Jun, 2023 (Thu) | Corpus Christi | Observance, Christian |
| 17 Jun, 2023 (Sat) | King's Birthday | Observance |
| 18 Jun, 2023 (Sun) | Father's Day | Observance |
| 21 Jun, 2023 (Wed) | June Solstice | Season |
| 22 Jun, 2023 (Thu) | Windrush Day | Observance |
| 28 Jun, 2023 (Wed) | Eid al-Adha | Muslim |
| 29 Jun, 2023 (Thu) | Eid al-Adha | Muslim |
| 12 Jul, 2023 (Wed) | Battle of the Boyne | Local Bank Holiday |
| 19 Jul, 2023 (Wed) | Muharram/Islamic New Year | Muslim |
| 27 Jul, 2023 (Thu) | Tisha B'Av | Jewish Holiday |
| 28 Jul, 2023 (Fri) | Ashura | Muslim |
| 29 Jul, 2023 (Sat) | Ashura | Muslim |
| 7 Aug, 2023 (Mon) | Summer Bank Holiday | Common Local Holiday |
| 15 Aug, 2023 (Tue) | Assumption of Mary | Observance, Christian |
| 28 Aug, 2023 (Mon) | Summer Bank Holiday | Common Local Holiday |
| 6 Sep, 2023 (Wed) | Janmashtami (Smarta) | Hindu Holiday |
| 7 Sep, 2023 (Thu) | Janmashtami | Hindu Holiday |
| 16 Sep, 2023 (Sat) | Rosh Hashana | Jewish Holiday |
| 18 Sep, 2023 (Mon) | Ganesh Chaturthi | Hindu Holiday |
| 23 Sep, 2023 (Sat) | September Equinox | Season |
| 25 Sep, 2023 (Mon) | Yom Kippur | Jewish Holiday |
| 27 Sep, 2023 (Wed) | Milad un Nabi (Mawlid) (Tentative Date) | Muslim |
| 30 Sep, 2023 (Sat) | First day of Sukkot | Jewish Holiday |
| 4 Oct, 2023 (Wed) | Feast of St Francis of Assisi | Observance, Christian |
| 6 Oct, 2023 (Fri) | Hoshana Rabbah | Jewish Holiday |
| 7 Oct, 2023 (Sat) | Shemini Atzeret | Jewish Holiday |
| 8 Oct, 2023 (Sun) | Simchat Torah | Jewish Holiday |
| 29 Oct, 2023 (Sun) | Daylight Saving Time ends | Clock change/Daylight Saving Time |
| 31 Oct, 2023 (Tue) | Halloween | Observance |
| 1 Nov, 2023 (Wed) | All Saints' Day | Observance, Christian |
| 2 Nov, 2023 (Thu) | All Souls' Day | Observance, Christian |
| 5 Nov, 2023 (Sun) | Guy Fawkes Day | Observance |
| 12 Nov, 2023 (Sun) | Diwali/Deepavali | Hindu Holiday |
| 12 Nov, 2023 (Sun) | Remembrance Sunday | Observance |
| 30 Nov, 2023 (Thu) | St Andrew's Day | Local Bank Holiday |
| 3 Dec, 2023 (Sun) | First Sunday of Advent | Observance, Christian |
| 8 Dec, 2023 (Fri) | Feast of the Immaculate Conception | Observance, Christian |
| 8 Dec, 2023 (Fri) | First Day of Hanukkah | Jewish Holiday |
| 15 Dec, 2023 (Fri) | Last day of Hanukkah | Jewish Holiday |
| 22 Dec, 2023 (Fri) | December Solstice | Season |
| 24 Dec, 2023 (Sun) | Christmas Eve | Observance, Christian |
| 25 Dec, 2023 (Mon) | Christmas Day | Bank Holiday |
| 26 Dec, 2023 (Tue) | Boxing Day | Bank Holiday |
| 31 Dec, 2023 (Sun) | New Year's Eve | Observance |
