ChatGPT for Planning a Japan Trip: Where It Helps and Where It Costs You Money

Ask ChatGPT to help you plan a trip to Japan in July. The route, probably fine. Everything else has a structural problem worth understanding before it costs you money.

The route part is no small thing: a 14-day itinerary through Tokyo, Kyoto and Osaka, neighbourhood by neighbourhood, days assigned to each city. AI is good at this because Japan is documented to death and the model has read thousands of guides. Whether the result is distinguishable from any Instagram travel blog is another matter: the same places, the same order, the same restaurants as always. Useful to get started. Not much beyond that.

What ChatGPT answers

These are the three questions anyone asks when planning Japan in summer, with typical answers from the model:

All of it sounds reasonable. Let's take it apart, because each answer has a different hole in it.

The flight price: an AI cannot give you a real price. It has no access to booking systems and doesn't see today's availability. That €700 to €1,200 range is a historical average. In July 2025, Madrid-Tokyo fares actually sat between €900 and €1,200, which means the lower half of the estimate simply didn't exist. Budgeting around the floor of a range that's no longer real is how you end up several hundred euros short.

The festival dates: matsuri don't always fall in the same week. The main Gion Matsuri parade in Kyoto is fixed, July 17. But plenty of smaller festivals shift dates every edition, and the Sumida River fireworks are the perfect example: cancelled in 2020 and 2021 because of the pandemic, back in 2022, and the exact date varies year to year. ChatGPT answers with whatever edition sits in its training data, which can be two or three years old. Booking a flight around that without verifying it is an expensive mistake.

The Osaka case: when the right advice is wrong

The advice to fly into Osaka is the clearest example of the problem. Historically it's true: Osaka usually comes out a bit cheaper than Tokyo. But from April 13 to October 13, 2025, Osaka hosted the World Expo. Hotels in the city went 40-60% above their normal rates, and flights into Kansai got noticeably more expensive for months. The "cheap" gateway was, that year, the more expensive of the two.

Why does the model fail here? GPT-4's training cutoff is April 2024. It knows the Expo exists as an announced event, but it never saw a single price from the period it actually ran. Its recommendation comes from patterns of previous years, when Osaka really was the budget option. It's not lying. It's answering from a world that no longer exists.

ChatGPT recommends Osaka as the cheap option. In 2025, with the Expo, it was the most expensive.

And this isn't a Japan quirk. Any city with a big event (an Olympics, a cup final, a massive trade fair) breaks historical patterns for weeks or months. An AI with a training cutoff cannot see it coming.

What Planisky does differently

At Planisky we start from the opposite end: the AI reasons, but over today's data. Real-time flight prices, not averages from two years ago. A festival calendar with this edition's dates, not the last one. And events that distort the market (an Expo, a World Cup, a Japanese national holiday block like Golden Week) factored in before we recommend anything.

The practical difference: not "Osaka is usually cheaper." Instead: for these dates, from Madrid, with what's happening in each city this year, here's what's available and here's what we recommend.

Where we are right now

It's not ready yet. It would be easy to put out a polished demo and promise things that don't work, but we'd rather be straight: we're in development.

The waitlist is basically that: we let you know when the features are ready. Planisky will be open to everyone, this isn't exclusive access. But the first 100 people to sign up get full access to the paid features at no cost, so they can use it from day one without restrictions.

If you've ever planned a trip with ChatGPT and found yourself fact-checking every answer by hand, you already know why this exists.