1970

August

 * 20 - Ace, companion of the Seventh Doctor, is born in England. (DW: Ghost Light)

Unknown date

 * "Mary" kills Myra Bennett in order to consume her heart. Human authorities do not manage to catch her. (TW: Greeks Bearing Gifts)

January

 * 3 - DW: Spearhead from Space Episode 1, the first colour episode of Doctor Who, the first of Season 7 and the first starring Jon Pertwee as the Third Doctor is broadcast. It launches the "UNIT era" of the series. Beginning in 1970, the number of episodes produced in each season is reduced considerably, and the show moves from a Fall to Spring broadcast schedule to a January-June schedule. Caroline John debuts as companion Liz Shaw, while Nicholas Courtney, as Brigadier Alistair Gordon Lethbridge-Stewart, becomes a series regular with this episode.
 * 10 - DW: Spearhead from Space Episode 2 First Broadcast
 * 17 - DW: Spearhead from Space Episode 3 First Broadcast
 * 24 - DW: Spearhead from Space Episode 4 First Broadcast
 * 31 - DW: Doctor Who and the Silurians Episode 1 First Broadcast

February

 * 7 - DW: Doctor Who and the Silurians Episode 2 First Broadcast
 * 14 - DW: Doctor Who and the Silurians Episode 3 First Broadcast
 * 21 - DW: Doctor Who and the Silurians Episode 4 First Broadcast
 * 28 - DW: Doctor Who and the Silurians Episode 5 First Broadcast

March

 * 7 - DW: Doctor Who and the Silurians Episode 6 First Broadcast
 * 14 - DW: Doctor Who and the Silurians Episode 7 First Broadcast
 * 21 - DW: The Ambassadors of Death Episode 1 First Broadcast
 * 28 - DW: The Ambassadors of Death Episode 2 First Broadcast

April

 * 4 - DW: The Ambassadors of Death Episode 2 First Broadcast
 * 11 - DW: The Ambassadors of Death Episode 3 First Broadcast
 * 18 - DW: The Ambassadors of Death Episode 4 First Broadcast
 * 25 - DW: The Ambassadors of Death Episode 5 First Broadcast. First UNIT-era appearance of John Levene as Sgt. Benton, who becomes a semi-regular for the next 6 years.

May

 * 2 - DW: The Ambassadors of Death Episode 6 First Broadcast
 * 9 - DW: Inferno Episode 1 First Broadcast
 * 16 - DW: Inferno Episode 2 First Broadcast
 * 23 - DW: Inferno Episode 3 First Broadcast
 * 30 - DW: Inferno Episode 4 First Broadcast

June

 * 6 - DW: Inferno Episode 5 First Broadcast
 * 13 - DW: Inferno Episode 6 First Broadcast
 * 20 - DW: Inferno Episode 7 First Broadcast. Caroline John leaves the series after this episode.