The team of the Penumbra are working to release accurate transcripts of each episode based on the final episode products. Transcripts can be found through the Penumbra Podcast website here, with specific transcripts linked under each episode's page, or directly in their google drive here.
There is also an unofficial fan account creating transcripts, @welcometothepenumbra on tumblr. A list of their complete transcripts are here.
History[]
A year after the first episode was released, Kevin Vibert and Harley Takagi Kaner had tried to create transcripts on their own but had only managed to make three, even with help[1]. They were completely overwhelmed by the amount of work it would take to get through every episode already released. As a result, fans in the community began the transcript project (@thepenumbrapodcasttranscripts on tumblr).
However, now that the Penumbra's production team has grown, Avi Meehan has taken the role of creating transcripts for each episode as it comes out[2]. They are working with the original tumblr team to complete transcripts for past episodes.