The greenback eased to 82.28 yen in Tokyo morning trade from 82.54 in New York late Wednesday.
The euro rose to $1.4574 from 1.4519. The single European currency fetched 119.90 yen against 119.83.
"The dollar is broadly under selling pressure," said Tohru Sasaki, strategist at JPMorgan Chase Bank in Tokyo.
"Investors' risk appetite is increasing on the back of brisk gains in stock markets amid growing expectation for economic recovery," Sasaki said.
"Investors are selling the dollar and the yen to finance investment" in riskier assets with higher returns.
US and European stocks soared Wednesday, with the Dow in New York closing near three-year highs, on strong earnings reports that beat Wall Street expectations, particularly in the technology sector.
The benchmark Nikkei stock index in Tokyo finished the morning session Thursday up 0.58 percent.
Against riskier assets, the dollar hit a 31-month low of 1,080.50 South Korean won, against 1,082.20 on Wednesday, and plunged to a 13-year low against the Malaysian ringgit, fetching 3.0080 from Wednesday's 3.0140.
The lingering US debt problem was also weighing on the dollar following Standard & Poor's warning on Monday it may downgrade US debt, dealers said.
"The market's focus is on the US debt problem, giving an additional blow to the greenback," Sasaki said.
Meanwhile, a smooth bond auction in Spain helped ease worries about the euro-zone debt problem, dealers said. Spain has been caught up in renewed fears over sovereign debt levels, propelled by Portugal requesting a bailout April 6.