Darren Foy, 40, from Southampton, his wife Sandra and their two children, missed the explosions by just half an hour after he finished the Boston Marathon in three and a half hours.
The chartered surveyor, who is chairman of the Lordshill Road Runners in Southampton and was competing in his fourth marathon, said: "There are reports here that the explosions came from a hotel at the finish line and I walked past there a few days ago to pick up my race number.
"It's such a soft target. There are hundreds of thousands spectators on the streets and 27,000 runners, so we got off lightly."
Brighton runner Abi Griffiths crossed the finish line of the Boston Marathon around ten minutes before the explosions happened.
She said: "It was as I was retrieving my bag that I heard an explosion, now everyone sort of looked around and there was a moment of disbelief and bewilderment, you didn't exactly know what had happened, but a few seconds after that suddenly it went into a state of chaos.
"The sound of the explosion, the ground shook underneath my feet a bit, I mean, just, I've never heard a bomb before but there was just that sixth sense that something bad had happened."
Former Metropolitan Police Officer Graham Whettone has told Daybreak that security protocols surrounding Margaret Thatcher's funeral will most likely be reviewed in light of what happened at the Boston Marathon.
He said: "If they need to advance [the plans] then they will do, there's different tactical options the police can employ at various events, they will just review those now, if they need to advancer them then they will do."