The following is a timeline of major events during the Myanmar civil war (2021–present), following the 2021 military coup d'état and protests. It was also a renewed intensity in existing internal conflict in Myanmar.
2021
March
25 March, the KIA seized the military base of Alaw Bum near the town of Laiza during the Battle of Alaw Bum airbase. As a response, on 11 April, the junta military launched a counter-attack to recapture the base using airstrikes and ground troops but had to retreat amidst heavy casualties. 26 March, the Karen National Liberation Army (KNLA) attacked a military base, killing 10 soldiers and taking others hostages in the first attack on the military since the protests began. 28 March- Dozens of protesters travelled to Myanmar's border areas to enlist in and train under one of the country's many insurgent groups, elevating the risk of a countrywide civil war. The first day of openly armed resistance against the coup where armed protesters in the town of Kalay fought back against soldiers and security forces attacking a protest camp, with clashes also taking place in villages in Kale township. 30 March- The Committee Representing Pyidaungsu Hluttaw proposes the formation of a "federal armed force" to combat the military. The Kachin Independence Army (KIA) has already been on the offensive against the military since February, and in late March the Arakan Army (AA) threatened to end its ceasefire with the military should the latter "persist in massacring civilians". Protesters increasingly begun arming themselves with homemade weapons such as guns in an attempt to defend themselves against attacks by the military. Simultaneously, clashes with soldiers and IED attacks against administrative buildings and police stations became more common as the trend of protesters using armed resistance rose.
April
4 April- seven insurgent groups who were signatories to the Nationwide Ceasefire Agreement aligned themselves with the Committee Representing Pyidaungsu Hluttaw, including the All Burma Student Democratic Front and the Karen National Union. 8 April- Taze becomes another frequent site of clashes when protesters fight back against soldiers with hunting rifles and firebombs in a battle that resulted in 11 protesters' deaths. The same day, the country surpassed 600 deaths related to anti-coup protests since 1 February. 10 April- when the Northern Alliance, comprising the Arakan Army, the Ta'ang National Liberation Army and the Myanmar National Democratic Alliance Army, attacked a police station in Naungmon, Shan State, killing at least 10 police officers. 16 April- pro-democracy politician Min Ko Naing announced the formation of the National Unity Government, with people of ethnic minority groups among senior roles and said that ousted leaders Aung San Suu Kyi and Win Myint would retain their positions and that members of the Kachin and Karen minorities would have top priority in the new parallel government. In the same announcement, Min Ko Naing asked the international community for recognition over the junta. 26 April- the Chinland Defense Force began an armed resistance in Mindat, Chin State. As a response, the junta cut off food and water supplies and declared martial law. Fighting began when a group of demonstrators outside the town's Aung San statue requested the release of six of their arrested colleagues, when a soldier of the regime allegedly fired at someone, prompting protesters to react.
May
5 May- the National Unity Government declared the formation of an armed wing, the People's Defence Force (PDF) to protect its supporters from military junta attacks and as a first step towards a Federal Union Army. 23 May- The People's Defence Force clashed with the Tatmadaw in the town of Muse on 23 May, killing at least 13 members of Myanmar's security forces. 26 May- Six Tatmadaw soldiers were killed in an ambush by the Chinland Defense Force in Hakha, Chin State. * the same day, the Tatmadaw launched airstrikes in Kayin State in response to the Karen National Liberation Army's capture and scorching of a Tatmadaw military base. Members of the Karenni People's Defence Force (KPDF) in Kayah State also captured and destroyed several Tatmadaw outposts near the state capital of Loikaw. The second-in-command of the Shanni Nationalities Army, Major General Sao Khun Kyaw is assassinated by the Myanmar Army. 29 and 30 May- the Tatmadaw used artillery and helicopters to strike PDF and KPDF positions in Loikaw and Demoso. 30 May- the Kachin Independence Army joined the anti-coup People's Defence Force battling junta troops in Katha Township, killing eight regime soldiers. Fighting was also continuing in Putao, Hpakant and Momauk Township.