Narrative:

Descending into ZZZ for a visual approach into runway xx I realized we were at 4;000 ft. 5 miles from the FAF. ATC wanted us to call the airport in sight to clear us for a visual and we had the airport in sight for the past 10 miles or so. I thought when we called it in sight to each other; the pm (pilot monitoring) told ATC and that we were clear for a visual approach. I set 2;700 ft. In the altitude selector and the autopilot began a descent. Passing through 3;000 ft. With the airport and surroundings in sight ATC said climb to 3;000 ft. And as we just had passed it I leveled the plane out and was about to climb back up from 2;900 ft. GPWS called out terrain terrain but this was not a factor because we saw the terrain and were clear of all obstacles. I disconnected the autopilot and climbed to 3;000 ft. As instructed. Then we came in and landed with no issue.this was a miscommunication between ATC; the pm; and PF (pilot flying). I thought the pm told ATC we had the visual and we were cleared for the visual approach. There was a small mountain below us but this was no factor and we were clear of it according to my visual sight and chart markings. The error I believe was when I set 2;700 ft. In the altitude window without communicating it clearly with my pm. If I would've brought it to his attention and he would have understood it; I believe he would have brought up that he had not heard ATC clear us for a visual approach yet like I thought he did. I was caught up in being too high for the approach and took an action that I had not completely communicated with my crew about.

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Original NASA ASRS Text

Title: Air carrier flight crew began a descent for a visual approach before being cleared; which resulted in an automated terrain warning and ATC directing a climb.

Narrative: Descending into ZZZ for a visual approach into Runway XX I realized we were at 4;000 ft. 5 miles from the FAF. ATC wanted us to call the airport in sight to clear us for a visual and we had the airport in sight for the past 10 miles or so. I thought when we called it in sight to each other; the PM (Pilot Monitoring) told ATC and that we were clear for a visual approach. I set 2;700 ft. in the ALT selector and the autopilot began a descent. Passing through 3;000 ft. with the airport and surroundings in sight ATC said climb to 3;000 ft. and as we just had passed it I leveled the plane out and was about to climb back up from 2;900 ft. GPWS called out terrain terrain but this was not a factor because we saw the terrain and were clear of all obstacles. I disconnected the autopilot and climbed to 3;000 ft. as instructed. Then we came in and landed with no issue.This was a miscommunication between ATC; the PM; and PF (Pilot Flying). I thought the PM told ATC we had the visual and we were cleared for the visual approach. There was a small mountain below us but this was no factor and we were clear of it according to my visual sight and chart markings. The error I believe was when I set 2;700 ft. in the ALT window without communicating it clearly with my PM. If I would've brought it to his attention and he would have understood it; I believe he would have brought up that he had not heard ATC clear us for a visual approach yet like I thought he did. I was caught up in being too high for the approach and took an action that I had not completely communicated with my crew about.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.