There are now just 200 places left in the 2017 Simplyhealth Great Birmingham Run with entries closing soon.
The annual half marathon takes place on Sunday, October 15 but anyone still wishing to enter will have to be quick.
Entries close at 10am on Thursday, October 5 in order to give organisers Great Run time to post out race packs and numbers to competitors.
However, if you are able to collect your race pack in person from the Great Run marquee at Aston University campus on Saturday, October 14, then you have until 10am on Monday October 9 to enter online.
After this time, entries will be completely closed.
Runners of all abilities can sign up now at GreatRun.org if they wish to take part in one of the UK's largest 13.1-mile runs.
The inaugural Birmingham International Marathon takes place on the same day meaning the half marathon will commence later than normal this year, with the afternoon start time allowing runners on the marathon to pass through the city centre first.
Anyone signing up for this year's Great Birmingham Run will get a guaranteed entry window to the 2018 Birmingham International Marathon.
Companies can also play their part in the half marathon with the Arcadis Business Challenge inviting firms of all shapes and sizes to compete for fastest-time trophies and all-important bragging rights.
They are raising funds for Cure Leukaemia's £1 million appeal to expand the Centre for Clinical Haematology at the Queen Elizabeth Hospital in Birmingham.
Families can also get involved with the Great Birmingham Mini and Junior Runs on October 14 at the city's Alexander Stadium running track.
All children who finish will receive a goody pack, medal and bottle of water.
The last date to enter the Mini and Junior Runs to have packs posted is 10am on Thursday, October 5.
Entries to collect packs in person will stay open until 5pm on Friday, October 13, after which entries for both junior events will be closed.
For more details and to enter visit GreatRun.org.
Grandfather Stuart Bailey, from Billbrook near Wolverhampton, has finished more than 50 running events dressed as everyone from Santa to the Jolly Green Giant to raise more than £20,000 for good causes.
He will be donning his seven-foot Peppa Pig costume to line-up for the Junior Mini Run and the half marathon to raise money for The Royal Wolverhampton NHS Trust Charity after they cared for his grandson George.
David Hart, communications director for the Great Run Company, said: "We've been overwhelmed with the response to this year's Great Birmingham Run, the Birmingham International Marathon and the mini and junior runs.
"The whole weekend will see thousands of people of all ages taking to the streets of Birmingham and the Alexander Stadium."