Six hours had been allotted for the specialists to do their work, but in the end they were finished in just four, city authorities said in a press release.
"Those guys are experts who plan everything well," police spokesman Oliver Pohl said.
The bombs were defused at 11 am, 11:56, 12:52 and the last at 1:57 pm.
It was the biggest operation of the decade for the bomb disposal unit (Kampfmittelräumdienst), as they worked to defuse four unexploded Second World War bombs found around a school in the northern port city.
For decades, pupils and teachers have attended Theodor-Storm School in Kiel's Wellingdorf district, unaware that four Second World War bombs lay unexploded on the school grounds.
The four American bombs were discovered during an aerial survey of the school grounds, reports Kieler Nachrichten.
One lay just metres below a school classroom, while another was directly next to a local kindergarten.
At 10am, experts began work defusing the three 250kg and one 500kg bombs.
Authorities evacuated around 4,500 people from homes and offices in the surrounding area while a disposal team got to work.
The city's information website advised locals to be patient, warning that the area could remain blocked off for up to eight hours.
Today's multiple defusal is just the latest batch of unexploded WW2 bombs discovered in Kiel.
During the war, the city's many arms factories made it a popular target for Allied attacks – and on August 6th and 7th, similar evacuations were carried out while experts defused two 250kg and 500kg bombs found in the city's Düstembrook and Wellingdorf districts.
SEE ALSO: 3,000 WW2 bombs still under Berlin