Upvote:0
Ireland and UK have an immigration agreement, the flight from Dublin to Edinburgh will be deal like a domestic flight
Upvote:1
From the Republic of Ireland site Department of Foreign Affairs and Trade listing visas for Ireland, under Requirements
the link to the Irish Naturalisation and Immigration Service Check if you need a visa will answer your question.
Selecting Papua New Guinea
for What nationality is shown on your passport or travel document?
, and then selecting Transit through Ireland. eg via an Irish airport
for How long do you want to stay in Ireland?
, gives the result:
You do not need a transit visa
You do not need a transit visa to travel through an Irish airport on your way to another destination.
Note that if you actually wanted to be a tourist in Ireland you would need a visa.