Source: By Oxfordian Kissuth - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=16005268
Lexis's United States Supreme Court Transcripts database provides access transcripts of oral arguments in cases heard before the U.S. Supreme Court from October 1979 to the present.
Westlaw's U.S. Supreme Court Oral Arguments database provides access to transcripts of oral arguments in cases heard before the U.S. Supreme Court from the 1990-91 Term to the present.
Access to these resources is limited to users who have valid accounts on Westlaw and/or Lexis.