The following clubs affiliated to the 2025/26 League. Clubs that affiliate to the 2026/27 League will be listed in due course.
- Basildon AC
- Benfleet Running Club
- Billericay Striders RC
- Braintree & District AC
- Brentwood Beagles AC
- Brentwood Running Club
- Castle Point Joggers
- Chelmsford AC
- City of Southend AC
- Colchester & Tendring AC
- Colchester Harriers AC
- Dagenham 88 Runners
- Daws Heath Harriers
- Dengie 100 Runners
- East Essex Triathlon Club
- Grange Farm & Dunmow Runners
- Great Bentley Running Club
- Halstead RR
- Harlow AC
- Harlow Running and Tri Club
- Havering AC
- Hockley Trail Runners
- Ilford AC
- Leigh on Sea Striders
- Loughton AC
- Mid Essex Casuals
- Orion Harriers
- Phoenix Striders
- Pitsea Running Club
- South Woodham Runners
- Springfield Striders RC
- SS Athletics
- Thurrock Harriers
- Tiptree Road Runners
- West Suffolk AC
- Witham Running Club