Labour has made 14,002 posts on Twitter and Facebook since 1 April, with the Conservatives on 8,653 and Liberal Democrats on 4,723.
Research from social media monitoring platform Yatterbox shows there has been a total of 31,011 tweets from all political parties – an average of 24 tweets per candidate.
All parties are discussing the same core issues. However, Labour has been the most outspoken, making more than double the number of mentions of the NHS than the Conservatives, with 5,792 mentions to 2,342 respectively.
Smaller parties including Plaid Cymru, the Green Party and UKIP are also voicing their opinions via social media, despite having far fewer candidates.
On tax, Labour has also topped the polls with 3,610 tweets to the Conservatives' 2,252, while the Lib Dems are on just 932.
However, on the economy the Conservatives come out on top with three times as many tweets (1,702) by candidates as Labour (648). The Lib Dems have also tweeted about the economy more than Labour.
Ben Carson, chief strategy officer at Yatterbox, said: "It is impressive that the candidates are being whipped effectively to communicate the national party priorities. The party machines are clearly working.
"In pure volume terms, Labour is clearly winning the social media war. It has significantly more candidates active on Twitter and Facebook than all other parties and is putting this advantage to good use.
"Yet when taking account of the number of candidates by party on social media we see stark results; the fact that Plaid Cymru is more noisy on the economy and the deficit than any other party is sure to raise a few eyebrows."