Jet Lag to Yokohama: How to Adjust From the US and Europe

Why does jet lag feel worse flying to Japan?

You cross the International Date Line heading west to east. A Wednesday afternoon departure from New York arrives in Yokohama on Thursday evening. Your circadian rhythm still reads Wednesday morning. The calendar jumps forward a full day. Your body has to compress its cycle. That is biologically harder than stretching it.

Westbound return trips are easier. You gain time. Flying from Tokyo to Los Angeles at 17:00 lands you the same day at 10:00. Your body stretches to fill the extra hours. Travelers consistently report milder symptoms heading home.

From US West Coast: 16 to 17 hours behind Yokohama

Los Angeles is 17 hours behind Yokohama in January. It is 16 hours behind in July. On 15 January 2026, when it is 12:00 in the port city, it is 19:00 the previous day in LA. You do not just lose a day. You lose a full night.

Typical flight: depart Los Angeles at 13:00, arrive Narita at 16:00 the next day. By the time you clear customs and reach the city via limousine bus or train (about 90 minutes), it is 19:00 or 20:00 JST. Your body wants to wake up.

What goes wrong: Travelers force themselves to stay awake for dinner. They crash at 21:00. They wake at 02:00 JST. Their sleep schedule fragments for a week.

What to do instead: Treat the arrival day as a long evening. Eat a light meal. Expose yourself to dim light after 20:00. Do not nap on the plane if you land after 16:00. That nap steals your first night's sleep drive.

From US East Coast: 13 to 14 hours behind Yokohama

New York is 14 hours behind this city in January. It is 13 hours behind in July. On 15 January 2026, 12:00 JST equals 22:00 EST the previous day.

Flight pattern: depart New York around 11:00, arrive Narita 14:00 the next day. That is a 14-hour flight arriving mid-afternoon. Your body thinks it is 01:00.

The trap: Mid-afternoon arrival feels manageable. You think you can push through to a normal bedtime. By 18:00 JST (05:00 your body time) you hit a wall. You fall asleep on a bench in Minato Mirai. You wake at 01:00 JST with no idea where you are.

The fix: Get outside immediately. Walk to the bus stop. Sit in sunlight during the taxi ride to your hotel. Do not enter a dark room until at least 17:00 JST. If you must sleep, limit it to one 20-minute power nap before 16:00.

From Europe: 8 to 9 hours behind Yokohama

London is 9 hours behind in January. It is 8 hours behind in July. Paris is 8 and 7 hours behind respectively. On 15 July 2026, 12:00 JST is 04:00 in Paris.

Flight: depart London 14:00, arrive Narita 10:00 the next day. You arrive in the morning. Your body thinks it is 01:00.

This is the best possible arrival scenario. Morning arrivals give you the strongest tool against jet lag: natural light. You have a full day ahead of you.

What fails: Travelers check into their hotel, close the curtains, and sleep until 15:00. They wake in the worst possible phase. Too late for afternoon light. Too early for a normal bedtime.

What works: Drop your bags. Go outside. Walk toward the water. The sun rises early here. On the June solstice, sunrise is at 04:26. On the December solstice, sunrise is at 06:46. You want light on your face between 10:00 and 15:00.

Should I book a morning or evening arrival to Japan?

Morning arrivals (from Europe, or from the US via a red-eye) are easier to manage. You have light exposure. You can stay active until a reasonable bedtime.

Evening arrivals (from the US West Coast, or from East Coast with a late connection) are harder. Your options narrow. You cannot use light to shift your clock because you need darkness to signal sleep.

Rule of thumb: If you arrive after 17:00 JST, keep lights dim after 20:00. If you arrive before 14:00 JST, stay in bright light until at least 16:00.

Light exposure and sleep strategy

Light is the single strongest cue for your circadian clock. Morning light advances your clock. It makes you sleepy earlier. Evening light delays it. It makes you sleepy later.

For eastbound travel, you want to:

• Day 1 (arrival day): Get at least two hours of outdoor light between 10:00 and 15:00 if you arrive in the morning. If you arrive in the evening, stay in dim light after 20:00.
• Day 2: Wake at 07:00 JST regardless of how little you slept. Get sunlight before 09:00. This resets your clock to local time faster than anything else.
• Day 3: You should feel normal by midday.

The mistake: Wearing sunglasses indoors. Your body needs full-spectrum light hitting your retinas. A hotel room at a few hundred lux does nothing. Outside at full daylight does everything.

Melatonin and other aids (Japan regulations)

Melatonin is not widely available in Japan. It is classified as a prescription-only drug. You cannot buy it at a pharmacy in the city.

What this means: Bring your own supply if you use it. Declare it at customs if you carry more than a one-month supply. Do not assume you can buy it locally.

Other aids that work:

• Caffeine: Use it strategically. One coffee at 08:00 JST on day one. None after 14:00. Caffeine has a half-life of about five hours. A 16:00 coffee still affects your sleep at 23:00.
• Exercise: A 20-minute walk at 07:30 JST on day two. Do not run at 21:00.
• Meals: Eat breakfast at local breakfast time (07:00 to 08:00). Do not skip it. Meal timing is a secondary time cue.

First 48 hours in Yokohama: what to do

Day one, morning arrival: Walk from your hotel toward Yamashita Park or the waterfront at Minato Mirai. Stay outside until 14:00. Eat lunch at a normal lunch hour (12:00 to 13:00). Do not nap. Go to bed at 21:00 JST.

Day one, evening arrival: Eat a light dinner. Take a warm shower. No screens after 21:00. Set an alarm for 07:00. Do not sleep past 08:00 even if you were awake until 03:00.

Day two: Wake at 07:00. Go outside before 09:00. Walk along the waterfront toward the Red Brick Warehouse. Eat breakfast. You will feel tired by 14:00. Push through. By 20:00 you will be ready for bed.

What ruins it: Napping on day one for more than 30 minutes. That nap reduces your sleep drive for the night. You lie awake at 02:00 JST. Then you oversleep. Then you repeat the cycle.

Why is flying west from Japan easier for jet lag?

Flying west from this port to the US means you gain hours. A 17:00 departure from Narita lands in Los Angeles at 10:00 the same day. Your body has been awake for 17 hours. It thinks it is midnight. The local clock says morning.

The strategy: Stay awake until 21:00 local time in Los Angeles. Expose yourself to light in the afternoon. Do not sleep on the plane unless it is the middle of the night at your destination. You will adjust in one to two days.

The exception: If you fly from here to Europe, the difference is smaller (8 to 9 hours). Most travelers adjust within two days without specific effort.

Japan does not observe daylight saving time. The entire country, including this city, stays at UTC+9 year-round. The time difference with your home city shifts twice a year when your country changes clocks. Check the current offset before you book.