Pauline Duthie has been head of the college since 2019 and will leave the school at the end of term 2 next year.
Mrs Duthie said she had spent 38 years working in education and was looking forward to a slower pace in the future.
More than 15 of those years had been as a principal at various schools, which was a lot of work, she said.
In her time as principal of Columba she has contributed strongly to the future-proofing of the school, such as the boarding house rebuild and the primary school redevelopment.
She believed she was leaving the school in a good position and now was the right time to move on, Mrs Duthie said.
She was concerned anything she had to say about the school would come over as "shameless self-promotion", but she really did think it was "an amazing place".
She was doing all she could to ensure a smooth transition for a new principal next year.
Although she would miss the school and the passion of the pupils, she was excited by the prospect of having more time to herself.
Some of her family lived overseas and now she would be able to plan visits outside school holiday times.
She was also looking forward to walking her dog at 9am, as opposed to 6am before school.
