The FA Cup was suspended for the duration of the war.
As with the 1916–17 season, Blackpool had to rely on a small nucleus of players supplemented by soldiers stationed in the town and the occasional league players as guests to make up the numbers. Again, they had to rely on staff from the Royal Army Medical Corps Depot (RAMC) based at Squires Gate. Edgar Chadwick, who had played for Blackpool in the 1904–05 season after a successful career at Everton, made two appearances for them again at the age of 48. George Beel, who went on to score 178 goals in 316 league games for Burnley, scored two goals in eleven appearances. Two RAMC men, Albert Moorcroft and Edmund Berry, who made their debut during this period, went on to sign professional terms with the club, as did Thomas Hunter, who played in the latter part of the season. Fred Pagnam, who had played for the club before the war, appeared in one Subsidiary Competition match.
The Principal competition for the 1917–18 season consisted of sixteen teams, with the same teams as the 1916–17 season:
Blackpool began the campaign on 1 September 1917, with a home match against Oldham Athletic, which they won 3–2, with all three goals coming from Kirrage, a soldier based at the RAMC depot. The Seasiders also fielded a new full back partnership of Dunn with Horace Fairhurst, both based at the RAMC Depot. Fairhurst would go on to sign permanently for the club after the war, before his death in 1921.
Blackpool lost just one of their first five matches, with three guest players scoring. However, they then went on a five-game losing streak from 6 October, when they lost 3–1 at Stockport County, to 3 November when they were beaten at home 6–0 by Liverpool. The Seasiders still struggled to raise a full team, and against Manchester United at Old Trafford on 8 December they could only field ten players, having to borrow a player from the home team. On 5 January 1918, Blackpool beat Everton 1–0 at home, but followed this up with a run of six defeats and one draw, including a 7–2 defeat at Everton, a 4–0 loss to Port Vale, and a 5–0 loss to Bolton Wanderers, in which Edgar Chadwick made his second appearance of the season. Results started to improve, and they ended the season with a run of six matches undefeated (four wins and two draws), including a 4–1 win over Blackburn Rovers, with Thomas Hunter scoring all four goals. By this time, Moorcroft and Fairhurst had "gone away on the draft" and the club once again were having to find new players, even though the season was drawing to a close.