The species is classed as ‘Fishes Royal’, meaning officers must take measurements, photos and complete reports.
The team is reminding the public to dial 999 and ask for the Coastguard in any coastal emergency.
Speaking on its Facebook page, a spokesperson for Furness Coastguard said: “Furness Coastguard were called out today to reports of a dead porpoise on Walney Island.
“Porpoise, dolphins and whale are classed as Fishes Royal and we need to take measurements, pictures and complete report forms.
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“If in danger on the coast or one of the four navigable lakes, Windermere, Coniston, Ullswater or Derwent Water, then dial 999 and ask for the Coastguard.”