The cost of a local stamp is reduced from today (Monday).
The 2p reduction applies to cards and letters posted locally.
The offer, which will be in place until December the 22nd, doesn’t apply to business mail.
The Post Office is stressing the cut is not connected to VAT changes which come into effect later.
"He enjoyed hearing the Manx national anthem!": King greets guests at Government House
His Majesty meets representatives of the Manx community at Garden Party
Crowds gathered in glorious sunshine to see the Monarch
Live blog: King Charles visits the Isle of Man
Updates from the Lord of Mann's first visit to the Island since ascending to the throne
King speaks of Island's 'enduring partnership' with the crown
King Charles III spoke in Tynwald this lunchtime