Sacramento, Trinity River salmon fishing guides Dave Jacobs June 7, 2015 Trophy Fish Sacramento, Trinity River salmon fishing guides. The Trinity River is now open to salmon fishing. The best Spring salmon fishing is in June and July. Over on the Sacramento River the salmon fishing season opens on July 16th and will remain open until December 16th. Another excellent salmon season is projected to return with 652,000 Sacramento River kings estimated in this years ocean abundance estimates. This year anglers will be allowed two salmon per person on the Sacramento River guided salmon fishing trips and four in possession as reported by Sacramento, Trinity River salmon fishing guides. The current flow schedule on the Sacramento River looks to be set at 7,200 this Summer with flows to drop later this Fall.