However, only those travelling between Ireland and the United Kingdom will be hit by the stoppage.
EU regulations make it clear that, when a flight with an EU airline or from an EU airport is cancelled, an airline is liable to pay for the cost of a hotel and subsistence for all those stranded as a result, until a replacement flight is provided.
The industrial action that begins at 1am tomorrow will be the first by Irish-based pilots in the airline's history. (Ryanair) are more resilient than others because they've never promised anything more than no-frills but deliver on what they promise.
They are taking action following a conflict over management's approach to the transferring of pilots between it's African and European bases. Ryanair apologised for the "regrettable" disruption and said it had done its utmost to avoid it.
The offer was made in a letter sent by Ryanair's Chief People Officer Eddie Wilson to Angela Kirk, Natonal Secretary of Forsa, a parent trade union of Irish Air Line Pilots' Association (IALPA) with which some of Ryanair's pilots who have threatened to strike are members.
However, the union said the strike is still likely to go ahead.
Fórsa, the workers union representing Ryanair cabin and ground crews, announced last week that they would hold a 48 hour strike between 25th and 26th July which could affect flights to and from locations including but not limited to Spain, Italy, Portugal and Belgium.
Ryanair said: "We regrettably must plan for some disruptions on Thursday, and try to minimise their impact, especially upon Irish customers and their families travelling on holidays to Portugal, France, Spain, Italy and Greece".
It said these are routes where customers could transfer "readily" to other flights today, tomorrow or at the weekend.
Customers who are travelling on a Ryanair flight to/from Ireland on Thursday 12 July and who have not already received an email or text notification, should expect that their flight will operate as planned.
Customer service teams are working until 10pm to help with refunds, flight transfers or booking ferries.
If you have not received a notification then Ryanair said that you should check in as normal on Thursday.
"It is unacceptable that competitor airline pilots are actively organising strikes by Ryanair's pilots when these airlines will be the direct beneficiaries of any such disruption", Ryanair said.
Ryanair has confirmed that it is to cancel up to 30 flights to and from Ireland on Thursday.