Joho's plan has been thwarted.
The Union on Monday cast aspersions on Mr Joho’s demands, noting the drive for self-rule could plunge the region into chaos.
"From our perspective, it is not helpful to talk about secession. The rhetoric may raise tension further than calm it down,” British High Commissioner Nic Hailey said on Monday.
Last week, Mombasa Governor Hassan Joho and his Kilifi counterpart Mr Amason Kingi were pushing for the secession of the Coastal region after “years of sideline by the government.”
Joho and Kingi cited political and economic marginalization in the call supported by a host of Opposition MPs from the region.
The Ambassadors who met the two governors for about five hours at Whitesands hotel in Mombasa on Monday, condemned the move terming it a recipe for chaos.
British High Commissioner Nic Hailey, French ambassador Antoine Sivan, European Union envoy Stefano Dejak and Danish ambassador Mette Knudsen attended.
Hailey added disintegration will not help and that the country needs urgent national dialogue to address dissenting voices.
"The country must have genuine conversations that will lead to improved development and prosperity," Mr Harley said after the meeting as quoted by the Star.
Dejak noted the call for secession was triggered by "strong feelings of exclusion".
"Now we have to strengthen inclusion and devolution. Logic inclusion can work best," he said, adding the 2010 constitution, which 67 per cent Kenyans approved, must be adhered to.
On his part Mombasa governors Hassan Joho maintained that there was need for talks on secession as it will help them air their views.
"You can oppose it but tell us why your are opposing it. We are more concerned about local and international legal frameworks to achieve the end," Joho said.