Sittingbourne station was opened on 25th January 1858 when the section of the East Kent Railway between Chatham and Faversham was opened.
A few years later a branchline to Sheerness was opened and commenced services on 19 July 1860.
At first direct trains to London were not an option. Travellers had to change at Chatham, where a horse and cart service took them to Strood, where trains were then operated to London. Trains direct to London commenced on 3rd December 1860.
Sittingbourne did not have a roof covering until around 1863 and a footbridge crossing between the two platforms was constructed in 1899 to compliment a subway.