"belated congratulations" is a correct and usable phrase in written English. It is usually used to express congratulations to someone after the time when the event or accomplishment warranted congratulatory messages. For example, "We heard about your successful business launch last month and wanted to send our belated congratulations!".
I hope you will join me in proffering belated congratulations.
I am a lifelong fan of The Times and am proud to see an accomplished woman at the helm, so a belated congratulations.
So, Tater Tots, please accept my belated congratulations.
She opened with "Dear Mr. Zezima," and wrote, in part, "The Duke and Duchess of Cambridge have asked me to send you their warmest thanks together with their belated congratulations to Lauren and Guillaume".
A belated congratulation is in order to longtime contest player Rhoda Feng, who was the lone respondent (and a correct respondent at that) to the December 30th contest.
A much-belated congratulations on your Emmy win.
Herzlichen Glückwunsch nachträglich means "heartfelt congratulations belated".
Being a terminologist, I care about word choice. Ludwig simply helps me pick the best words for any translation. Five stars!
Maria Pia Montoro
Terminologist and Q/A Analyst @ Translation Centre for the Bodies of the European Union