The number of visitors surpassed 3 million in March - the first time they've ever gone above that level.
Arrivals have been boosted by factors including the weak yen.
The Japanese currency is languishing at multi-decade lows versus the dollar, making the country a cheap destination for travellers.
That drew tourists to enjoy Japan's famous cherry blossom season.
But if that's all a big boost for the country's economy, other numbers out Wednesday paint a less pretty picture.
The latest Reuters Tankan index of business sentiment showed the mood turning sour at big companies.
Manufacturers and service firms both saw falling confidence in April.
Companies cited factors including uncertainty over the outlook for China's economy, and weak demand among consumers at home.
Some said price hikes had stopped shoppers spending.
The weak yen is a factor there too, as it's driven the cost of imports ever higher.
The effect showed up in trade figures as well, with exports jumping 7.3% in March, boosted by the helpful exchange rate.
