'Trekking in the Scottish highlands,’ he captioned the snap.
Fans were quick to comment on the snap with one writing, 'Scotland has never looked so hot', while another read, 'Marry me!'
Arthur recently revealed that he is dating Lizzie Friend whom he went Instagram official with in September.
'She's really sweet and they make a very nice couple. He took her to Royal Ascot this summer as his date,’ a source previously told the Daily Mail.
Arthur is the grandson of Princess Margaret, who is 25th in line to the throne.