The number of marriages celebrated last year more than halved compared to 2019.
Central Statistics Office (CSO) figures show civil marriage ceremonies were the most popular overall.
Just over 9,500 marriages took place in 2020, including 314 same-sex couples.
That is down 53 per cent on the previous year.
The average age for those getting married rose last year, for a groom it was 35.7 years and a bride 37.8 years.
For same-sex couples the age was 40.
Commenting on the report, statistician Carol Anne Hennessy said: “There were 9,523 marriages in Ireland in 2020 including 314 same-sex marriages. This equates to a crude (unadjusted) marriage rate of 1.9 per 1,000 population. The number of marriages celebrated in 2020 fell by 53.1 per cent from 2019, reflecting the impact of Covid-19 restrictions.
“The timing of weddings may also reflect the impact of Covid-19 restrictions. The cooler month of December was the most popular for opposite-sex weddings, while February was most popular for same-sex marriages. April was the least favoured month to tie the knot for all couples.
“Friday and Saturday continue to be the most popular days to tie the knot for opposite-sex couples, while Friday followed by Thursday were the most favoured days to wed for same-sex couples. Sundays and Wednesdays were the least popular days of the week to marry for all couples.”
Atheist Ireland has said “our laws must catch up with this reality, and stop giving privilege to the Catholic Church," in response to the popularity of civil ceremonies over religious ones.
A statement from the group read: “For the first time ever, in 2020, there were more Civil marriages than Catholic marriages in Ireland. 42.1 per cent of marriages were Civil, compared to 34.6 per cent that were Catholic.
“Yet most of the children of these couples will have to attend a state-funded school run by the Catholic Church, where they will be taught Catholic doctrine about marriage, including that marriage is only between a man and a woman.
“Marriages by all traditional Churches, including Christian and others, are now an overall minority at 43.4 per cent. This includes 42.1 per cent Catholic, 1.2 per cent Church of Ireland, and 7.6 per cent other religions.
“Of the other 14.3 per cent of marriages, 7.8 per cent were humanist and 6.7 per cent were spiritualist. Legally, humanist marriages are counted as secular while spiritualist marriages are counted as religious.”