- Joes Fish Shop4Takeaway/sandwich shopMerthyr TydfilCF46 6DN
- Juggy's Plaice5Takeaway/sandwich shopMerthyr TydfilCF48 1LE
- Julie's Castle Tea Rooms5Restaurant/Cafe/CanteenMerthyr TydfilCF47 8RE
- Julie’s deli & desserts3Takeaway/sandwich shopMerthyr TydfilCF47 9JH
- Just Perfect Catering4Restaurant/Cafe/CanteenMerthyr TydfilCF46 6RD
- K&T Store5Retailers - otherMerthyr TydfilCF47 9LP
- K.F.C.4Restaurant/Cafe/CanteenMerthyr TydfilCF48 1HY
- KV’s5Retailers - otherMerthyr TydfilCF48 1ND
- Kam Wah4Takeaway/sandwich shopMerthyr TydfilCF48 2BY
- Kaneschar Stores4Retailers - otherMerthyr TydfilCF48 1SJ
- Kellys Kakes5Other catering premisesMerthyr TydfilCF47
- Kepak - Merthyr4Restaurant/Cafe/CanteenMerthyr TydfilCF48 2TA
- Kepak Ltd / St Merryn'sExemptManufacturers/packersMerthyr TydfilCF48 2TA
- Key Vapours CBD StoreExemptRetailers - otherMerthyr TydfilCF47 8DF
- Keyvapours LTDExemptRetailers - otherMerthyr TydfilCF48 1HT
- Kidz Den Afterschool Club5Hospitals/Childcare/Caring PremisesMerthyr TydfilCF46 5ER
- King Kebab4Takeaway/sandwich shopMerthyr TydfilCF47 8UN
- Knights Chemist LTDExemptRetailers - otherMerthyr TydfilCF47 9SB
- Knights Chemist LtdExemptRetailers - otherMerthyr TydfilCF48 3AL
- Kooler Nightclub5Pub/bar/nightclubMerthyr TydfilCF48 1AY
- Koz Turkish Restaurant3Restaurant/Cafe/CanteenMerthyr TydfilCF47 8AP
- Kurd Halal4Retailers - otherMerthyr TydfilCF47 8AE
- LA BOCATA5Restaurant/Cafe/CanteenMerthyr TydfilCF48 1AY
- Lady Charlotte Cafe4Restaurant/Cafe/CanteenMerthyr TydfilCF48 3EH
- Lauren Flynn T/A Llwyn Yr Eos5Other catering premisesMerthyr TydfilCF48
- Lemon Pepper HoldingsAwaitingRestaurant/Cafe/CanteenMerthyr TydfilCF48
- Lidl5Retailers - supermarkets/hypermarketsMerthyr TydfilCF48 2TA
- Lifestyle Bedlinog Stores4Retailers - otherMerthyr TydfilCF46 6RG
- Lifestyle Express3Retailers - otherMerthyr TydfilCF48 1DR
- Little Acorns @ Ysgol Y Graig5Hospitals/Childcare/Caring PremisesMerthyr TydfilCF48 2RD
- Little B's Bakes5Other catering premisesMerthyr TydfilCF47
- Little Inspirations @ Gellideg5Hospitals/Childcare/Caring PremisesMerthyr TydfilCF48 1ND
- Little Lambs - Pentrebach4Hospitals/Childcare/Caring PremisesMerthyr TydfilCF48 4DR
- Little Learners - Pantysgallog Ltd5Hospitals/Childcare/Caring PremisesMerthyr TydfilCF48 2AD
- Little Rascals Pre-School5Hospitals/Childcare/Caring PremisesMerthyr TydfilCF48 4BJ
- Llwyn Onn Guest House5Hotel/bed & breakfast/guest houseMerthyr TydfilCF48 2HT
- Llwyn-yr-Eos Inn4Pub/bar/nightclubMerthyr TydfilCF48 1AX
- Llysfaen Residential/Respite Home3Hospitals/Childcare/Caring PremisesMerthyr TydfilCF47 9PT
- Londis4Retailers - otherMerthyr TydfilCF48 3LT
- Londis Stores5Retailers - otherMerthyr TydfilCF47 9YP
- Love Food4Takeaway/sandwich shopMerthyr TydfilCF48 3HB
- Lucky Leprechaun Ltd T/A The Celtic Bar5Pub/bar/nightclubMerthyr TydfilCF48 1AY
- Maddys5Retailers - otherMerthyr TydfilCF48 1HT
- Maes Y Bryn Registered Care Home4Hospitals/Childcare/Caring PremisesMerthyr TydfilCF46 5NB
- Magic Wok3Takeaway/sandwich shopMerthyr TydfilCF47 8UN
- Mango House3Restaurant/Cafe/CanteenMerthyr TydfilCF48 2PN
- Marks & Spencer5Retailers - supermarkets/hypermarketsMerthyr Tydfil
- Marmaris kebab3Takeaway/sandwich shopMerthyr TydfilCF48 3HB
- Martyrs Community Club4Restaurant/Cafe/CanteenMerthyr TydfilCF47 9JH
- Masonic Hall5Other catering premisesMerthyr TydfilCF47 8RF