The no-frills carrier that the overhaul was also partly driven by the "rapid growth" of Ryanair Sun, which is its profitable Polish charter airline.
Ryanair Sun will now offer over 10 aircraft to Polish tour operators. That is double the five planes it offered for the summer 2018 season.
The group will begin redundancy consultations with affected staff, and will offer transfers to Poland to minimise redundancies.
"We regret these base aircraft reductions at Dublin for winter 2018, but the board has decided to allocate more aircraft to those markets where we are enjoying strong growth (such as Poland)," said chief operating officer Peter Bellew.
"This will result in some aircraft reductions and job cuts in country markets where business has weakened, or forward bookings are being damaged by rolling strikes by Irish pilots."
He added: "If our reputation for reliability or forward bookings is affected, then base and potential job cuts such as these at Dublin are a deeply regretted consequence".
Yesterday, dozens of Ryanair's Ireland-based pilots staged their third 24-hour strike in an ongoing dispute over working arrangements including annual leave and promotions. The action has led to the cancellation of 16 flights affecting some 2,500 customers.
And on Monday, Ryanair revealed that first-quarter profit dropped more than a fifth on higher fuel costs and pilots' salaries.
Profit after tax slid 22 per cent to 309.2 million euros (USD 362 million) in the three months to the end of June compared with a year earlier.
Ryanair also faces strikes elsewhere this week despite group efforts in recent months to improve pay and conditions.
Cabin crew in Spain, Portugal, Belgium and Italy are going on strike on Wednesday and Thursday, leading to the cancellation of 600 flights over two days and affecting 100,000 passengers.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)