Jenner told radio host John Catsimatidis that she was mulling whether she could accomplish more as an outsider “working the perimeter of the political scene” or “from the inside.”
California Senate incumbent Senator Dianne Feinstein, who turned 84 in June, has not said whether she plans to seek re-election in 2018.
Jenner has been Donald Trump supporters and could be expected to run as Republicans.
Jenner has criticised Trump for ending an Obama-era directive to allow transgender students access to public school bathrooms of their chosen gender. “From one Republican to another, this is a disaster,” she said in February.
In June, USA TODAY reported on Jenner’s political views and her on-again, off-again relationship with Trump.
“For me, philosophically, I’m on the Republican side. I have conservative views. But I’m also trans,” she said. “…I would much rather convince Republicans to do better with (LGBT) issues than to try to convince Democrats to lower taxes and have less regulations and less government. I work hard, mostly behind the scenes, to change (Republicans’) views.
“When I sit down with Republican senators, they’ll tell me they’ve never met a trans person before and they’ll mention their faith,” she continued. “I explain how faith has played a big part in what I have done and am doing right now. Just sitting at the table with someone, that can change people’s minds.”