SEGA Bass Fishing and Space Channel 5 Part 2 arrive on PSN and XBLA this summer.
The two HD ports had been pencilled for an "early 2011" arrival.
"Space Channel 5 Part 2 and SEGA Bass Fishing are definitely coming to XBLA and PSN. Look for them sometime in late summer," SEGA brand manager Ben Harborne told Joystiq.
SEGA Bass Fishing, Space Channel Part 2, Sonic Adventure and Crazy Taxi make up the Dreamcast Collection. You can buy the latter two games individually online now, each priced 800 Microsoft Points or £6.29.
Sadly, the ports aren't very good - the sound in particular being "universally dreadful".
Keza MacDonald stamped a disappointing 5/10 on the four-game Dreamcast Collection earlier this year - a score greatly helped by her fondness for the delightfully bonkers Space Channel Part 2.
"It's the quality of the ports as much as the quality of the games that lets this collection down. They aren't just unimproved, they're actively worse," she wrote.
"The fact this is the best SEGA can come up with after years of waiting for Dreamcast re-releases does not say much for the publisher's ability to evaluate the worth of its own back catalogue," she added. "We can only hope for better in the future."