Today’s Cheapest Petrol and Diesel in Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield: The Full Report

A comprehensive breakdown of fuel prices in the Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield area. We analyze the market data to help you save on your next fill-up.

Jonathan Mathews
Jonathan Mathews
Automotive Data Analyst
10+ years automotive industry
Last Updated Saturday, 7th February 2026 at 04:50
23
Local Stations
24
Brands (CF Area)
17.0p
Max Price Gap
#30
UK Ranking REGION
Key Takeaways
  • Cheapest petrol: 124.9p at Sainsbury's
  • Potential savings: Up to £9.35 per tank
  • 87 stations tracked across 24 brands

Motorists in Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield are currently enjoying some of the lowest fuel prices in the UK, ranking in the top 25% nationally. Over the past week, E10 petrol prices in CF have Increased 0.9p (0.7%)

According to our latest data feed from the Competition and Markets Authority (CMA), selecting the right forecourt in Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield could save you up to 17.0p per litre. For an average 55-litre family car, that's a saving of over £9.35 on a single tank.

Market Competition: Moderate competition

Competition Level: High

Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield has 87 active fuel stations across 24 different brands, with a brand diversity index of 0.28 - indicating healthy market competition.

The price spread between cheapest and average stations is 6.3p, revealing significant price differences - shop around to save!

Today's Best Value

Cheapest E10 Petrol in Cardiff, Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield:
124.9p at Sainsbury's, 6A Welsh Designer Outlet Village

Cheapest B7 Diesel in Cardiff, Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield:
132.9p at Sainsbury's, 6A Welsh Designer Outlet Village

As expected, the supermarket chains are leading the price war in Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield, aggressively undercutting the major oil brands.

Fuel Type Availability

E10
Unleaded (E10)
Widely available
82 / 87 Stations (94.3%)
E5
Super Unleaded (E5)
Moderate availability
58 / 87 Stations (66.7%)
B7
Diesel (B7)
Widely available
80 / 87 Stations (92%)
SDV
Premium Diesel
Moderate availability
35 / 87 Stations (40.2%)

Top 10 cheapest petrol stations (E10)

Here is the verified list of the most affordable places to buy standard Unleaded petrol in Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield today.

PETROL LEADERBOARD Live Data
1
Sainsbury's
6A Welsh Designer Outlet Village , CF32 9ST
124.9p
BEST PRICE
2
TESCO
Cowbridge Road Bridgend , CF31 3SQ
124.9p
+0.0p
3
TESCO
Brewery Ln Bridgend , CF31 4AP
124.9p
+0.0p
4
Asda
Pyle Industrial Estate, Pyle Cross, Pyle, Bridgend , CF33 6BU
126.6p
+1.7p
5
Texaco
MFG Tondu, Maesteg Road, Tondu , CF32 9BT
126.9p
+2.0p
6
BP
Bridgend by-pass, Bridgend , CF31 3NB
127.9p
+3.0p
7
Texaco
MFG Pencoed, 11 Coychurch Road, Pencoed , CF35 5NH
127.9p
+3.0p
8
Texaco
MFG Laleston, North Side, Laleston Nr Bridgend , CF32 0LY
127.9p
+3.0p
9
Asda
Rhondda Road, Pontypridd , CF37 1HF
128.9p
+4.0p
10
Sainsbury's
Brown Lennox Retail Park, Ynysangharad Road , CF37 4DA
128.9p
+4.0p

Top 10 cheapest diesel stations (B7)

For diesel drivers, the price variance can often be even higher. The following stations are currently offering the best value for B7 Diesel in the Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield area.

DIESEL LEADERBOARD Live Data
1
Sainsbury's
6A Welsh Designer Outlet Village , CF32 9ST
132.9p
BEST PRICE
2
TESCO
Cowbridge Road Bridgend , CF31 3SQ
132.9p
+0.0p
3
TESCO
Brewery Ln Bridgend , CF31 4AP
132.9p
+0.0p
4
Asda
Pyle Industrial Estate, Pyle Cross, Pyle, Bridgend , CF33 6BU
133.8p
+0.9p
5
TEXACO
G H GRIFFITHS & SONS, NISA LOCAL, COWBRIDGE ROAD, BRIDGEND, CF31 3BD, BRIDGEND, Wales , CF31 3BD
133.9p
+1.0p
6
BP
Bridgend by-pass, Bridgend , CF31 3NB
134.9p
+2.0p
7
Texaco
MFG Laleston, North Side, Laleston Nr Bridgend , CF32 0LY
135.9p
+3.0p
8
Texaco
MFG Tondu, Maesteg Road, Tondu , CF32 9BT
135.9p
+3.0p
9
TESCO
Tesco Stores Ltd Crickhowell Road St. Mellons Cardiff , CF3 0EF
135.9p
+3.0p
10
Texaco
MFG Pencoed, 11 Coychurch Road, Pencoed , CF35 5NH
136.9p
+4.0p

How to save on fuel in Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield

While choosing the cheapest station is the easiest way to save, changing your driving habits can also make a significant difference to your monthly spend.

Drive Smoothly

Aggressive acceleration and heavy braking can increase fuel consumption by up to 40% in stop-and-go traffic around Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield.

Reduce Weight

Carrying an extra 50kg in your boot increases fuel consumption by 1-2%. Clear out unnecessary items.

Market Analyst Commentary
CFP Research Team

"Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield benefits from strong market competition with 24 brands operating across 87 stations. Ranking in the top 25% nationally makes this an excellent area for fuel savings, while with a 6.3p price gap between cheapest and average stations, careful selection could save £3.47 per tank."

For more detailed savings, explore our Interactive Fuel Map to scan the entire region visually.

Frequently Asked Questions

As of February 7, 2026, the cheapest station is Sainsbury's at 124.9p per litre.

There is currently a 17.0p difference between the cheapest and most expensive stations in Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield. For a standard family car, this equals a saving of £9.35 per tank.

Yes, currently supermarkets (Sainsbury's) are offering the lowest prices in the area.

Our Analysis Methodology

Data Collection
  • Direct feed from UK Government CMA API
  • Updated every 30 minutes via automated polling
  • Zero user-submitted prices (prevents manipulation)
  • Last sync: 05:09, 07 Feb 2026
Quality Assurance
  • Automated anomaly detection for pricing errors
  • Cross-referenced against regional averages
  • Outliers flagged for manual review
  • Historical data tracked for trend validation
Verified Data Source: All prices displayed on this page are sourced directly from the Competition and Markets Authority's official fuel price transparency scheme. We do not accept payments from retailers to alter rankings or display preferential pricing.
Data Accuracy & Methodology

Source: We retrieve real-time pricing data directly from the UK Government CMA Open Data Scheme.

Frequency: Data for Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield was last synchronized at 04:50 today. We update our database every 4 hours to ensure accuracy.

Disclaimer: While we strive for 100% accuracy, forecourt prices can change instantly. The prices listed above were correct at the time of our last server sync.

Editorial Policy

CheckFuelPrices is independent. We do not accept payment from fuel brands to alter rankings. Read our full policy.

📈 7-Day Price Movement
Petrol (E10) 0.9p
Was: 130.3p → Now: 131.2p
Diesel (B7) Stable
Was: 138p → Now: 138.4p

Visualise the Savings

View 20 local stations on our interactive map.

Open Live Map
Popular Brands in Rumney, Trowbridge, Llanrumney, St Mellons, Castleton, Marshfield
Sainsbury's TESCO Asda Texaco BP