Diesel up 13.9%. Petrol down 0.9%. That 14.8-percentage-point gap is the most striking number to emerge from the first month of the Iran crisis in Spain – and it tells the story of a government tax cut that worked for one fuel but not the other. Based on Fuelconomy's dataset of 11,867 Spanish stations tracked between March 5 and April 4, 2026, Gasóleo A climbed from €1.582/L to €1.802/L while Gasolina 95 E5 actually fell from €1.571/L to €1.557/L. The Canary Islands, entirely dependent on maritime fuel supply disrupted by the Strait of Hormuz closure, saw diesel prices surge by as much as 28%.
Key facts from the data:
This analysis is based on Fuelconomy's historical price dataset covering 11,867 stations across Spain from March 5 to April 4, 2026. Daily national averages, minimums, and maximums are calculated from official government price feeds via the Ministry for Ecological Transition. City-level data covers 144 cities with 20 or more reporting stations. Current prices shown at the end of this article update automatically from Fuelconomy's live database.
The Iran crisis hit Spanish forecourts in two distinct phases. Between the start of US-Israeli strikes on Iran on February 28 and the government's emergency tax package on March 22, both diesel and petrol surged in lockstep. But after the VAT cut from 21% to 10% and the suspension of hydrocarbon excise duties took effect, the two fuels sharply diverged.
Diesel peaked at a national average of €1.944/L on March 21 – a 22.9% jump in just 16 days. The tax cut brought immediate relief, dropping the average to €1.789/L by March 22. But that relief proved temporary. By April 4, diesel had crept back up to €1.802/L and was still climbing. The tax cut saved diesel drivers roughly €0.14/L compared to the peak, but it could not override the underlying global supply pressure on middle distillates.
Petrol told a completely different story. After peaking at €1.803/L on March 21, Gasolina 95 E5 collapsed to €1.611/L by March 22 and continued falling to €1.557/L by April 4 – actually ending the month below where it started. The combined tax relief of roughly €0.30/L was enough to fully absorb the crude-driven increase for petrol but not for diesel.
Why the divergence? Diesel's cost structure is more exposed to the Hormuz closure. Roughly 20% of global oil supply transits that strait, but the disruption disproportionately affects middle distillates (diesel, kerosene, heating oil) because refinery margins on these products spiked far harder than on gasoline. European diesel also competes with Asian demand, and Asian buyers – who rely even more heavily on Gulf supply – were bidding up every available barrel.
Week 1 (March 5 – 11): The initial shock
Diesel jumped from €1.582/L to €1.794/L in just six days – a €0.212/L increase. Petrol rose from €1.571/L to €1.676/L. Brent crude had already passed $100/barrel. Lines appeared at forecourts across the Costa del Sol and the Canary Islands as panic buying set in.
Week 2 (March 12 – 18): Climbing toward the peak
The upward march continued. Diesel reached €1.881/L by March 18, petrol hit €1.759/L. At this point, a 50L tank of diesel cost €94.05 – a full €15.00 more than two weeks earlier. The Spanish government announced its €5 billion emergency package on March 20.
Week 3 (March 19 – 25): Tax cuts hit, diesel and petrol diverge
March 21 was the high-water mark: diesel at €1.944/L, petrol at €1.803/L. When the VAT cut and excise suspension took effect on March 22, the drop was immediate. Diesel fell €0.155/L in a single day. Petrol fell €0.192/L – and kept falling. By March 25, petrol was already back below its pre-crisis level. Diesel was not.
Week 4 (March 26 – April 4): The slow creep back
Petrol stabilised around €1.55/L – essentially back to normal. Diesel, however, started creeping up again. From a post-tax-cut low of €1.760/L on March 27, it rose steadily to €1.802/L by April 4. The global diesel supply crunch was reasserting itself despite Madrid's fiscal intervention.
The seven Canary Island cities in our dataset tell a dramatically different story from mainland Spain. While the national diesel average rose 13.9%, Canary Island cities saw increases of 22% – 28%. The reason is straightforward: the Canary Islands import 100% of their fuel by sea, much of it routed through supply chains that depend on tankers transiting or originating near the Strait of Hormuz.
There is an irony here. Canary Island fuel prices started the month significantly lower than the mainland – La Laguna diesel was €1.201/L vs the national average of €1.582/L – because the islands benefit from a special tax regime (IGIC instead of mainland VAT and lower excise duties). Even after the 28.4% surge, La Laguna diesel at €1.542/L is still cheaper than the national average of €1.802/L. But the rate of increase is what hurts household budgets: a driver in La Laguna who fills up a 50L tank twice a week went from paying roughly €120/week to €154/week – an extra €136/month.
Petrol on the islands told a similar story. La Laguna Gasolina 95 E5 rose 17.8%, Telde and Santa Cruz both around 16.5%. On the mainland, petrol fell. The Canary Islands' geographic isolation from the European refinery network means the government's tax cuts could not fully offset the raw supply cost increase.
Across Fuelconomy's dataset of 144 Spanish cities, the range in diesel prices on April 4 was enormous – from €1.528/L in Telde to €1.914/L in Ibiza. That is a spread of €0.386/L, or roughly €19 per 50L fill-up.
Ibiza and Palma sit at the top for the same reason as the Canaries – island logistics – but with an added factor: tourist-season pricing. With Easter approaching and summer bookings already at record levels, forecourt operators on the Balearics had little competitive pressure to absorb costs.
On the mainland, the Basque Country (San Vicente de Baracaldo) and northern cities like Oviedo and Torrelavega also landed among the most expensive, reflecting higher regional tax structures and the premium that northern Spain pays for refinery access.
For most Spanish drivers, the price in their nearest major city is what matters most. Here is how the seven largest mainland markets performed:
(Based on Fuelconomy data, March 5 – April 4, 2026)
The diesel-petrol split is consistent across every major city. Not a single mainland city saw petrol rise. Zaragoza petrol dropped 3.4%, the steepest fall among major cities – enough to save a regular driver roughly €3 per fill-up compared to a month earlier. Diesel, meanwhile, rose between 12% and 15% everywhere on the mainland.
On March 20, Prime Minister Pedro Sánchez approved a €5 billion emergency package. The two headline fuel measures were a VAT reduction from 21% to 10% and a suspension of excise duties on hydrocarbons, effective from March 22. Together, these measures were designed to deliver roughly €0.30 – €0.40/L in savings at the pump.
The data shows this worked – partially. Looking at the March 21 peak versus the April 4 close:
For petrol, the tax package fully absorbed the crisis-driven increase and then some. Drivers filling up with Gasolina 95 E5 are actually paying slightly less than they were before the conflict began. For diesel, the tax cut clawed back roughly €0.14/L of the €0.36/L peak increase – but still left drivers paying €0.22/L more than before the war.
The measures are set to run until June 30, 2026, with a review clause tied to April's inflation data. If CPI does not exceed the April 2025 level by more than 15%, the VAT rate reverts to 21% in June. Given that Spanish inflation jumped to 3.3% year-on-year in March – the highest since 2024 – an extension seems likely if the Hormuz situation does not resolve.
Diesel dominated the headlines, but the snapshot data reveals an interesting picture across all 18 fuel types tracked in Spain:
(Based on Fuelconomy data. Fuel types with fewer than 100 stations excluded for clarity.)
The pattern is unmistakable. Every diesel variant rose sharply – Gasóleo B (agricultural/industrial diesel) climbed the most at 18.2%, which directly feeds into food and freight costs. Every petrol variant fell slightly after the tax cut. Gases Licuados del Petróleo (autogas/LPG) barely moved at –0.9%, making it the most crisis-resistant fuel in the dataset. Gas Natural Comprimido (CNG) rose 10.9%, reflecting the separate gas market disruption from Qatari LNG supply cuts.
For fleet operators and farmers: Gasóleo B at €1.451/L represents an 18.2% increase that hits operating margins directly. The government's emergency package included a €0.20/L subsidy specifically for farming and professional transport. Check whether your fleet fuel cards qualify via the Agencia Tributaria portal.
The bottom line for a typical Spanish diesel driver – someone filling a 50L tank roughly twice a month:
For frequent drivers filling up weekly, the numbers are worse: roughly +€44/month or over +€500/year. And that is using the April 4 average – many cities are above €1.85/L, which pushes the annual extra cost past €600.
Petrol drivers, on the other hand, are essentially unaffected. A Gasolina 95 E5 driver filling up twice monthly actually saves about €1.40/month compared to early March.
Three ways to save right now:
The snapshot data above covers March 5 – April 4, 2026. But prices keep moving. Here is where things stand right now across the Fuelconomy network of {[STATION_COUNT_spain]} Spanish stations:
Compare real-time prices in the cities most affected by the crisis:
Use Fuelconomy to check current prices at {[STATION_COUNT_spain]} stations across Spain before your next fill-up – especially if you are a diesel driver, where the price gap between the cheapest and most expensive nearby station can easily exceed €0.15/L. (Live data)
Based on Fuelconomy's data from 11,867 stations, Gasóleo A rose from €1.582/L to €1.802/L between March 5 and April 4, 2026 – an increase of 13.9% or €0.22 per litre. The peak was €1.944/L on March 21, before the government's emergency tax cut brought partial relief.
The Spanish government's emergency package – a VAT cut from 21% to 10% plus suspended excise duties – delivered roughly €0.30 – €0.40/L in tax relief. For petrol, this more than offset the crude-price increase. For diesel, the underlying global supply disruption (Hormuz closure, Asian demand, refinery margin spikes on middle distillates) was too large for the tax cut to fully absorb.
The Canary Islands import 100% of their fuel by sea, and their supply chains are heavily exposed to tanker routes disrupted by the Strait of Hormuz closure. While mainland Spain can access pipeline-connected European refineries, the islands depend on maritime deliveries. La Laguna diesel rose 28.4% vs 13.9% nationally.
On March 20, 2026, Madrid approved a €5 billion emergency package. Key measures: VAT on fuel cut from 21% to 10%, excise duties on hydrocarbons suspended, a €0.20/L subsidy for farming and professional transport, and a 5% electricity consumption tax scrapped. These measures took effect March 22 and run until June 30, 2026.
Among the five countries Fuelconomy tracks – France, Spain, Italy, Portugal, and the United Kingdom – Spain remains the cheapest for diesel as of April 4. But the gap is narrowing: Spanish diesel rose 13.9% during the period, and the price difference with other Fuelconomy markets has compressed significantly.
A 50L tank of Gasóleo A cost €79.10 on March 5 and €90.10 on April 4 – an increase of €11.00 per fill-up. A driver filling up twice a month is paying roughly €22 more per month, or €264 more on an annualised basis.
Use Fuelconomy's live price comparison tool. Across {[STATION_COUNT_spain]} Spanish stations, the national spread on diesel is {[PRICE_SPREAD_spain_gasóleo-a]}/L – meaning the cheapest station in your area could save you several euros per fill-up compared to the nearest one. Check the live widget above for current averages by city. (Live data)
Gases Licuados del Petróleo (autogas) barely moved during the crisis – down 0.9% to €0.931/L, roughly half the cost of diesel. If your vehicle supports LPG conversion (typically €1,500 – €2,500) and you drive over 15,000 km/year, the payback period at current spreads is under 18 months. Gas Natural Comprimido is more volatile – it rose 10.9% due to separate LNG supply disruptions – but still costs less than diesel in absolute terms.