From the release, they expect to release it in 1-2 weeks on regular Coinbase.
"Coinbase Consumer — per our previous guidance, Coinbase Consumer will list assets only after they are listed on Coinbase Pro and Prime. We plan to add support for ETC on Coinbase Consumer when sufficient liquidity is established. We expect this to occur approximately 1–2 weeks after trading begins on Pro and Prime. Ethereum was not supported on Coinbase Consumer until after the fork, therefore there are no corresponding Ethereum Classic credits for Coinbase Consumer customers."