Three of the men claimed their human rights had been breached because statements they made to police without lawyers present had been used as evidence.
A fourth man argued he had been treated unfairly when interviewed as a witness.
The Strasbourg-based European court ruled no prejudice had been caused to their right to a fair trial.
Three of the men were convicted in 2007 over a botched attempt to repeat the attacks in London of 7 July 2005.
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A fourth defendant, Ismail Abdulrahman, was convicted in 2008 of assisting one of the failed bombers and failing to disclose information about the planned attacks.
He was sentenced to 10 years imprisonment, which was reduced to eight years on appeal.
Judges at the ECHR said: "It has been convincingly established that at the time of the impugned police interviews there was an exceptionally serious and imminent threat to public safety, and that this threat provided compelling reasons which justified the temporary delay of all four applicants' access to lawyers."
Because the bombs did not explode, police were able to recover forensic material from the scenes of the attacks and CCTV images of the bombers were also available.
All the four bombers are from the Horn of Africa. Omar and Mohammed were born in Somalia, Ibrahim in Eritrea and Osman in Ethiopia. They all fled or went into hiding after the attempted attacks.