What to pack

Pack at least double what you think you need. Trip extensions, dropped pens, lost bags, and accidental waste all happen.

In your carry-on (always)

  • All your insulin - never put insulin in checked baggage
  • Pen needles or syringes in the original packaging
  • Glucose meter and test strips
  • Fast-acting glucose (tablets, gel, juice boxes) for hypoglycemia
  • A printed list of all medications, doses, and the prescribing doctor
  • A copy of your most recent prescription - paper backup of what your US pharmacy app shows
  • A doctor's letter stating that you have diabetes and need to carry insulin and needles (not strictly required for TSA but helpful for international screening)

In checked baggage (only as a backup)

If you absolutely must split your supply, keep no more than half in checked baggage. The cargo hold can reach temperatures below freezing on long flights, which damages insulin. The risk of a lost bag also means your insulin must be there when you land.

Cooling

An insulated travel pouch with a small reusable cooling element keeps insulin within safe range for a typical transatlantic flight. Specialist brands sell pouches rated for insulin specifically and are TSA-friendly.

TSA security screening with insulin

TSA medication rules for insulin are well-established - TSA screens millions of diabetic passengers every year. The procedure is straightforward, but knowing it in advance avoids hold-ups.

Declaration

You do not need to formally declare insulin at TSA, but it is easier to mention it at the screening area. Say "I have insulin and supplies" and the officer will guide you through the appropriate screening.

Liquid limits

The 100ml (3.4oz) liquid restriction does not apply to medications including insulin. Your insulin vials, pens, juice boxes, and gel for hypoglycemia are all allowed in unlimited quantities in carry-on.

X-ray and body scanners

Insulin can go through the X-ray machine without harm. Insulin pumps and continuous glucose monitors (CGMs) should not go through full-body scanners (millimeter wave or backscatter X-ray); request a pat-down instead. Most TSA officers are familiar with this; if not, ask for a supervisor.

Needles and syringes

Pen needles and syringes are allowed in carry-on when accompanying insulin. The TSA recommendation is to keep them in original packaging with a pharmacy label, but this is not strictly required.

In-flight storage and time zones

Storage during the flight

For a transatlantic flight (typically 7 to 10 hours from the US east coast to Spain), keep insulin in your insulated pouch in the cabin. Do not put it in the overhead bin if you can avoid it - temperature varies more there than at seat level. Do not ask the flight crew to refrigerate it in the galley unless you have a multi-day supply at risk; the galley refrigerator is shared with food service and temperatures can drop too low.

Time zones

Spain is 6 hours ahead of US Eastern time (5 hours during US daylight saving overlap). Crossing east to west, your daily clock effectively shrinks; west to east, it expands.

For most insulin regimens:

  • Long-acting (basal) insulin: on the day of travel east (US to Spain), some adjustment may be needed to avoid stacking doses. The general approach is to delay the next dose by approximately the time difference, but this depends on your specific insulin and your usual dosing time. Discuss with your US doctor before you travel.
  • Rapid-acting (prandial) insulin: follow the meals. Take rapid-acting insulin with each in-flight meal as you would at home, scaling for what you actually eat.
  • Insulin pump users: change the pump clock to local time on landing, or in stages during the flight. Discuss the right approach with your endocrinologist.

If you are unsure, lean toward slight under-dosing in the air rather than over-dosing. Hypoglycemia at altitude is more dangerous than mild hyperglycemia.

Spanish customs on arrival

Spain (like other Schengen countries) has straightforward rules for personal-use medication in checked or carry-on baggage. For insulin specifically:

  • Personal-use quantities are not declared at customs. Insulin in original packaging clearly labeled for the named traveler does not require any special declaration on arrival.
  • No documentation is required for a typical trip's supply (up to about 3 months of insulin).
  • If asked, a US prescription bottle label is sufficient evidence. A doctor's letter is helpful but not required.
  • Pen needles and syringes are unrestricted for personal use.
  • Glucose meter and test strips are unrestricted.

Spain has no specific declared-quantity threshold for non-controlled prescription medication. Quantities clearly in excess of a single trip's needs (for example, a year's supply) could potentially raise questions, but this is rare in practice.

Controlled medications (opioids, benzodiazepines, ADHD stimulants) have stricter requirements - see our controlled medications guide. Insulin is not a controlled substance.

If you arrive without enough

Insulin loss is a same-day situation

If you arrive and your insulin is missing, damaged, or insufficient, do not wait. Spanish pharmacies will not dispense without a Spanish prescription, and a US prescription cannot be filled directly. The first step is to get a Spanish prescription.

Three realistic routes depending on urgency:

Less than 24 hours of supply

Go to Urgencias (the ER) immediately. Bring whatever evidence you have - US prescription, pharmacy app screenshot, US doctor's letter, or even just the empty packaging. The ER will issue an emergency Spanish prescription and dispense from the in-hospital pharmacy.

24 to 72 hours of supply

A private in-person doctor with same-day availability is appropriate. EUR 50 to EUR 150 in major cities.

More than 72 hours of supply

An online consultation with The Holiday Doctor is suitable for continuation of an established regimen. You will need US prescription evidence and current insulin details. Same-day issue if approved. EUR 50, only if a prescription is issued.

Buying insulin in Spain

Spanish pharmacies stock all major insulin types. To collect a Spanish prescription you will need:

  • The REMPe collection code from your Spanish prescription (delivered to your inbox if the prescription is electronic, which most are)
  • Photo ID (your passport)
  • A pharmacy - any pharmacy in Spain can fulfill a REMPe prescription, not just the one you visited

Cost

Insulin in Spain is significantly cheaper than in the US, even at private pharmacy retail prices. A 3-month supply of long-acting basal insulin typically costs EUR 30 to EUR 60. A 3-month supply of rapid-acting insulin in pen form is in a similar range.

This is a private pharmacy purchase, so you pay up front. Save the receipt - most US travel insurance will reimburse insulin replacement when the original supply was lost or damaged.

Important. If you are running short on insulin and cannot reach a doctor or pharmacy the same day, go to Urgencias. Insulin is one of a small number of medications where missing a dose has rapid consequences for type 1 diabetes and many type 2 regimens.