Forty wedding guests who had travelled from across the UK and America were among those evacuated from the Waterfoot Hotel in the Waterside.
Groom Donal Doherty, who is getting married today to Margaret Johnston, was checking in when he was told he and his guests would have to leave. They and staff were evacuated across the Foyle bridge to Da Vinci's Hotel, part of the Garvan O'Doherty Group that owns the Waterfoot.
Hundreds of students also faced huge disappointed when their school formal dance at the hotel had to be cancelled.
The evacuation began yesterday shortly before lunch-time just as Mr Doherty and his guests were hoping to relax and enjoy a rehearsal dinner last night.
Speaking to the Belfast Telegraph, Mr Doherty said it was the last thing his already stressed bride needed.
He added: "Our guests have travelled from across the UK and America so they are tired and have just arrived in Derry, so instead of coming here we are having to ring around and let them know they have to go somewhere else.
"I was hoping to stay here tonight along with my groomsmen ahead of our wedding in Lough Eske.
"It is the first time in Derry for some of our guests, they will be arriving in the middle of a bomb alert and I don't know what they are going to think.
"I was hoping to check into the bridal suite and have a bit of peace for a couple of hours to write my wedding speech; looks like that's not happening any time soon."