Yes, most car rental companies in Santa Coloma de Gramenet require a valid credit card in the primary driver's name. The credit card is usually used for the security deposit and any additional charges or fees.

Unfortunately, it is unlikely that you can rent a car in Santa Coloma de Gramenet without a credit card. A credit card is generally required by car rental companies as it serves as a form of security and guarantees payment for any damages or additional charges.

To rent a car in Santa Coloma de Gramenet, you will typically need the following documents:

• A valid driver's license from your home country (international driver's license is recommended but not always required)
• A valid passport or national identification card
• A valid credit card in the primary driver's name

It is important to check with the specific car rental company for any additional documentation requirements.

While it is possible to find a car rental in Santa Coloma de Gramenet without a reservation, it is highly recommended to make a reservation in advance. This ensures that you have a guaranteed vehicle available and may help you secure a better rate. Additionally, during peak travel seasons, it can be challenging to find a car rental without a reservation.

When returning a rental car in Santa Coloma de Gramenet, follow these steps:

1. Check the car for any damages and ensure all personal belongings are removed.
2. Park the car in the designated return area or parking lot.
3. Return the car keys to the rental desk or drop-off box, as instructed by the rental company.
4. Request a receipt or confirmation of the car's return for your records.

It is important to return the car on time to avoid any additional charges or penalties.

If you return the rental car late in Santa Coloma de Gramenet, you may be charged additional fees. These fees are usually calculated based on an hourly or daily rate, and the amount can vary depending on the rental company. It is important to communicate with the rental company if you anticipate being late, as they may be able to provide options or extensions.