In Ireland there are both Fastpitch Softball Leagues (National) as well as Slowpitch Softball Leagues (Provincial). Softball Cups are organized on a National basis for Provincial League teams, and the Champions of each province can compete for the Softball Ireland National Club Championship (SINCC). The SINCC Champions have the opportunity to represent Ireland in the European Club Championships. In addition there have been a number of Weekend Softball Leagues for Slowpitch teams which give players and teams the chance to compete against other teams from outside their own Provincial League.
Here are links to various Softball Ireland Competitions:
Fastpitch Softball is basically a Women’s Competitive version of Baseball, and differs from the Coed / Mixed version of Softball played in Ireland since the 1980s, as the pitching is fast and not in a soft arc, as in the recreational version of the sport (hence the name softball). There are 9 players in a Fastpitch Softball team, like in Baseball as opposed to 10 in Co-Ed (Mixed) Recreational Softball.
The Fastpitch Ireland programme dates from the early 2000s, when two Women’s teams were created, and then in the 2010s, the Softball Ireland National team (who played in both the World Championships and European Championships) was started.
In 2019-20 the first Softball Ireland Irish National Fastpitch League began, playing all its matches on the turf pitch at the National Indoor Arena in Blanchardstown, Dublin 15. Unlike the earlier Fastpitch Softball in Ireland, this is Coed / Mixed, with an equal representation of Men to Women (5:5).
Here are links to various Fastpitch competitions in Ireland and Internationally, involving Ireland teams:
Fastpitch Softball Leagues
Softball Ireland Cups
The Softball Ireland National Club Championship (SINCC) is the Premier Slowpitch Softball Competition in Ireland, played between the winners of the Regional Leagues. The Brian Walshe Cup (Previously the ISA Cup) is second on the Order of Merit and the Irish Open Softball Trophy (IOST) third. Below this are the Regional (Provincial) Leagues. [Reference: 1]
References:  The Baseline – Irish Softball Community | Facebook Group (2020) Colum Lavery’s [Softball Ireland President]Reply to Post by Enda Mulcahy, 12 January 2020 [Internet] Available from: https://www.facebook.com/groups/2272568132795300/permalink/2870358163016291/ [Accessed 12 January 2020]
The Softball Ireland Brian Walshe Cup is the Premier Cup Competition in Ireland, played since 2008, and preceded by the Softball Ireland / Irish Softball Association Cup (1995-2007), the Irish Baseball & Softball Association / Federation Softball Championship (1990-1994) and the Aughinish All-Ireland Challenge (1986-1988).
Irish Softball Cup
SI Brian Walshe Cup 2008-Present; SI Cup 1995-2007; Irish Softball Championship 1990-1994; Aughinish All-Ireland Challenge 1986-1988
Softball Ireland Cups (All-Time Overview)
Softball Ireland Cups 1986-Present
Softball Ireland Cups (Decade / Era Overview)
Aughinish All Ireland Challenge (Softball) 1986-1988
Irish Softball Championship 1990-1994
Softball Ireland Cup 1995-2007
Softball Ireland Brian Walshe Cup 2008-Present
ISA Championship (Seasons): 1990 1991
IBSA Cup Championship (Seasons): 1992 1993
IBSA 6:4 Cup Competition (Seasons): 1997 1998
ISA Cup (Seasons): 2002 2004 2006