European CD Single
"Sometimes" (Radio Edit) – 3:55"Sometimes" (Soul Solution Mid-Tempo Mix) – 3:29
Japanese CD Single
"Sometimes" (Radio Edit) – 3:55"...Baby One More Time" (Sharp Platinum Vocal Remix) – 8:11"...Baby One More Time" (Davidson Ospina Club Mix) – 5:40
The Singles Collection Boxset Single
"Sometimes" (Radio Edit) – 3:55"I'm So Curious" – 3:35