The three-kilometre route - from Haverlands Lane at Worsbrough Bridge to Smithy Wood Lane, Dodworth - received a £400,000 grant from Sustrans, funded by the Department of Transport.
Work on the stretch - identified due to its high use - included the laying of an environmentally-friendly, all-weather surface made from 16,000 recycled tyres to boost grip for walkers, cyclists and horse riders.
The previous pathway was a combination of natural ground and compacted stone, which would become muddy during the winter months.
The ribbon was officially cut on Wednesday by Coun John Wilson, vice chair of the Trans Pennine Trail Executive Board, along with representatives of Sustrans and Barnsley Council, the Trans Pennine Trail national office and the two contractors, Barnsley Countryside Rangers and KBI UK.
Final works on information boards, wildlife trail markers and additional seating will be installed during the next few months to complete the project.
Coun Chris Lamb, cabinet spokesperson for environment and transport, said: “The Trans Pennine Trail is an absolutely incredible asset and I’m delighted we’ve been able to improve it and protect it for use by people of all ages and levels of mobility.
“This week we’ve also had the first community volunteer event on this section of the trail co-ordinated by Sustrans after a long 14 months of Covid restrictions.
“The volunteers have been planting wildflowers on the bank and car park area to improve the biodiversity on this section of the trail.
“It’s great to see recycled tyres put to such good use, making the trail more comfortable to use and also improving drainage.”
More funding bids have been submitted to improve other sections of the trail through the borough which, if successful, will see work carried out before the end of March 2022.
New projects including a six-kilometre corridor from Barnsley town centre to Royston - via Smithies - have been announced as well as links between Stairfoot, Ardsley and Goldthorpe, and work on the Trans Pennine Trail in Elsecar totalling £4.63m.
Rosslyn Colderley, director for Sustrans in the north of England, added: “It’s been great to work in partnership with Barnsley Council and the Department for Transport to help improve this section.
“It’s part of work we’re carrying out across the UK to raise the standard of the network for all abilities.
“We aim to create paths which everyone can access whether that is walking, cycling, using a mobility scooter, double buggy, or an adapted bike.
“There’s lots of work to be done and we are continually looking for more funding to improve the network.
“We are keen to hear from anyone who may be able to help support this work to create paths for everyone.”