You have signed the contract. You have the keys. The fridge is empty, the lights work, and you have no idea whose name the bills are in or whether the previous tenant's password is still on the router. This is the boring part of moving in, the part the landlord does not help with, and the part that costs you €200 a month if you get it wrong. Here is what to do in the first week.
Bills into your name: cambio de titular, not new contract
When you move in, ask the landlord for the most recent bills for electricity, gas (if there is piped gas) and water. What you actually need from each bill is the supply identifier: the CUPS code for electricity and gas, the contract number for water. With those, you can do a cambio de titular instead of a new contract.
Why this matters. A cambio de titular is essentially "same supply, different name on the bill". It is typically free, it does not trigger a power cut, and it does not reset your contracted potencia (capacity). A new contract starts from scratch, charges a connection fee, may switch the supply off for a few hours, and resets the terms.
You almost always want the cambio de titular. Two exceptions. If the previous tenant left unpaid bills (in which case you want a clean new contract so the debt does not stick to your name), or if the contracted potencia or tariff is wildly wrong for you and the supplier will not change it without a new contract.
The major suppliers to know. Electricity distribution in Catalonia runs mostly through Endesa's network; the retailer (who you pay) can be Endesa, Naturgy, Iberdrola, Holaluz or any of a dozen others. To switch retailer, just call the new one with your CUPS and they handle it. Gas: Naturgy is the dominant retailer for piped gas. Water: Aigües de Barcelona is the monopoly, with online cambio de titular through their portal and a phone line that works if the portal does not recognise you.
If you are not confident on the phone in Spanish, the bigger providers have English lines, with mixed wait times. A gestor will do all of this for €30 to €60 if it is worth it to you.
Potencia and tariffs, and why your bill is twice your friend's
Spanish electricity bills have two main components: the contracted potencia (capacity in kW) and the energy you actually use. You pay a fixed daily fee for the potencia regardless of consumption.
A small flat for a single person can usually run on a low potencia, around 3.45 kW. A larger flat with electric heating, an oven, an induction hob and a busy household often has 5.75 kW or higher. The higher the potencia, the higher the daily fixed fee, and it adds up fast across a year. If the trip-switch never trips even when the oven, kettle, heater and dryer are all running, you are probably paying for more potencia than you need.
You can change your contracted potencia once a year for free. Use a few months of bills to calibrate before changing.
Tariffs come in two main shapes. Tarifa libre is a fixed price per kWh at the market rate. Tarifa regulada PVPC is variable, set by the government, cheaper on quiet hours (overnight, mid-morning) and more expensive at peak times. If you can shift the dishwasher and the washing machine to overnight, PVPC saves real money. If you cannot, fixed is calmer to live with.
Spanish consumer association OCU and the CNMC comparator publish neutral comparators each year. Do not just stay with whoever the previous tenant had; they may have been on a discounted employee tariff that does not transfer to you.
Collective energy purchases (compra colectiva). One lever most newcomers miss. Platforms such as Spock pool thousands of households together a few times a year and negotiate a single rate with the suppliers, usually beating what you would get signing up on your own. It is free: you register, add your supply point, and you are switched automatically if a purchase you qualify for closes. The campaigns run in windows (the early-2026 round ran February to March), so the move is to register and wait for the next one to open rather than chase a specific deal. It covers electricity and sometimes gas, not internet.
Butano gas bottles in 2026
Plenty of older Barcelona buildings still use butano: orange gas bottles you swap at the corner shop or get delivered. If your kitchen has a hob with a flexible orange tube and no fixed gas pipe, you are on butano.
Butano has its quirks. A bottle costs around €18 to €22 and lasts a couple of months for a single person making one cooked meal a day. Heavy users (gas water-heater on butano) burn through them in three to four weeks. You can have bottles delivered: the Repsol or Cepsa truck has set delivery times for each street, and you book on the Repsol app. The water heater on butano is fine in spring and autumn; in a January cold snap with an old heater, you will get five minutes of warm shower before it goes cold. Budget €40 to €80 a month in winter for cooking and hot water on butano, on top of electricity.
If you have piped gas (gas natural canalizado), the bill goes through Naturgy or another retailer and the cambio-de-titular logic above applies.
Internet without two weeks of dead time
The single biggest unforced error new tenants make is cancelling their old internet contract before the new one is active. ISPs in Spain handle "translado" (transfer) badly. The clean approach is to take a new contract at the new address with a fresh activation, and let the old one terminate after the move. You pay a few days of double billing. You do not lose two weeks of WiFi.
The four big consumer ISPs are Movistar, Vodafone, Orange and MásMóvil, plus smaller resellers (Pepephone, Lowi, Digi) who piggyback on the same fibre networks at lower prices and with thinner customer service.
The order of operations. Check fibre availability at the new address before signing the lease; most central Barcelona buildings have multiple operators wired in, but some older buildings only have one. Order the new contract with an activation date one or two days before your move-in. Once the new line is live, cancel the old one (use portabilidad if you are keeping a phone number; otherwise straight cancellation; expect a 15-minute retention call). Hold on to the old router for the equipment-return deadline; missing it costs €70 to €150.
A word on operators, going by the running consensus in Barcelona's English-speaking community rather than any lab test.
Vodafone draws the most complaints: speeds below what was sold, weak service, and a specific trap where the “fibre” you ordered turns out to be DOCSIS (coax) in some buildings rather than true fibre. Check the connection type before you sign, or avoid it.
Movistar (and its cheaper sibling O2, plus low-cost operators like Lobster that ride the same Telefónica network) is the premium, it-just-works option. Coverage and speed are rarely the problem; the price is. Worth it if you value reliability over saving a few euros a month.
Digi is the budget favourite (around €30 for 1 Gbps), with one catch: it is only worth it where Digi has installed its own “smart fibre” (fibra propia) in your building. Without that, you are on the Movistar network up to Digi's backbone, with thinner support and a more mediocre experience. Ask whether your building has Digi smart fibre before committing, and note you may need an NIE to sign up.
Co-ops and resellers such as Som Connexió, Pepephone and Lowi are well regarded for service and value, usually running on the big networks at lower prices. A sensible middle path.
What most people miss
The cambio de titular timing trap. If you do the electricity change in week three and the previous billing cycle straddles your move-in, you will get charged for some of the previous tenant's usage. Read the bill, calculate the meter reading on your move-in date (photograph the meter that day), and dispute the difference if it does not add up. Suppliers refund quickly when challenged with numbers.
Two more practical bits. The Spanish electrical-installation certificate (Boletín de Instalación Eléctrica) is what the new retailer asks for if there has been a power cut or if the flat has not been occupied for a year. Ask the landlord for it on day one; if there is no recent one, factor in €100 to €200 for an electrician to issue a new one. And the building's community fees are often invoiced separately to the gas and electricity; ask whether they are included in your rent or billed to you directly, because newcomers regularly assume "everything is in the rent" and discover otherwise three months in.
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