The following is a chronology of events regarding the nuclear crisis at the Fukushima Daiichi nuclear power station in Fukushima Prefecture,triggered by the March 11 earthquake and tsunami.
| March 11 | Magnitude 9.0 quake forces power plant's Nos. 1-3 reactors to suspend operations automatically (Nos. 4-6 reactors were shut down at the time for regular checks); Prime Minister Naoto Kan declares nuclear emergency, directing local residents in 3km radius of plant to evacuate |
| March 12 | Kan inspects stricken plant; radioactive steam escapes from No. 1 reactor's containment vessel; hydrogen explosion rips No. 1 reactor building; government expands evacuation zone to 20km radius of plant |
| March 14 | Hydrogen explosion rocks No. 3 reactor building; No. 2 reactor's fuel rods exposed as water level recedes inside reactor vessel |
| March 15 | Kan scolds Tokyo Electric Power Co. (Tepco) officials at company's head office; explosion heard near suppression chamber of No. 2 reactor's containment vessel; explosion also heard at No. 4 reactor; government directs residents in 20-30km radius of plant to stay indoors |
| March 16 | No. 3 reactor's containment vessel thought to be damaged,forcing workers to evacuate |
| March 17 | Ground Self-Defense Force helicopters drop water on No. 3 reactor building; fire engines spray water from ground |
| March 18 | Nuclear safety agency gives crisis involving Nos. 1-3 reactors preliminary rating of 5 on international nuclear accident scale of 7 |
| March 19 | Tokyo firefighters spray water on No. 3 reactor; government announces detection of higher-than-allowable levels of radioactive materials in raw milk in Fukushima Prefecture, spinach in Ibaraki Prefecture |
| March 20 | No. 5, 6 reactors enter stable condition called "cold shutdown" |
| March 21 | Workers evacuated from No. 3 reactor after smoke seen spewing out |
| March 22 | Large concrete pump drops water on No. 4 reactor |
| March 23 | Elevated level of radioactive iodine detected in water-treatment plant in Tokyo, prompting metropolitan government to urge people not to give tap water to infants |
| March 24 | Three workers exposed to elevated levels of radiation at No. 3 reactor's turbine building; metropolitan government rescinds drinking restriction for infants |
| March 25 | Government urges people within 20-30km radius of plant to evacuate on their own |
| March 26 | Iodine with radioactivity 1,850 times allowable level found in seawater near drainage for No. 1 reactor |
| March 27 | High levels of radioactive water found in tunnels near turbine buildings for Nos. 1-3 reactors |
| March 28 | Highly contaminated water found in basement of No. 2 reactor's turbine building; Tepco says plutonium detected on plant premises on March 21, 22 |
| March 30 | Tepco Chairman Katsumata announces decommissioning of Nos. 1-4 reactors |