Championship strugglers Jersey ended 2013 as they slumped to their ninth defeat in 10 games.
The islanders had a lot of possession early on, but Will Hooley's long-range penalty put Moseley ahead.
Winger Matt Williams sprinted from the half-way line, evading a Jack Burroughs tackle, for a converted try.
Niall O'Connor's penalty reduced the deficit, but there were no points for either side after the break despite intense pressure from Jersey late on.
The visitors were camped near the line as they pushed to level the scores at a series of reset scrums, but they lacked the killer instinct when it really mattered and Moseley's defence stood firm.
Prop Ben Evans came on as a second-half replacement for the home side against his former club, but ended the match in the sin-bin after a fight between the packs.
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Jersey's interim head coach
“We certainly got loads and loads of possession and we're just not doing enough with it at the moment”
"The Jersey boys played with a lot of heart. [But] We did our homework on them and I think it paid off a little bit," Evans later told
BBC Radio Jersey.
"We were very much up for this this game, we're a semi-pro team and you've just got to play with lots and lots of heart. I'm not saying Jersey didn't, but that's all we can rely on sometimes because we do two sessions a week together.
"I don't want to see Jersey go down, it's a dogfight down the bottom and it's a tough old league."
Out-of-form Jersey have now scored only three points in their last 160 minutes of action and interim head coach Steve Boden, who was put in charge after Ben Harvey's departure as director of rugby, faces a tough task to turn his team's fortunes around for the second half of the campaign.
"We got a losing-bonus point at a hard place to play but it's not something that's going to put a smile on faces," he said.
"We should be coming here and winning. We probably made one defensive error in the first half and they scored seven points and that was pretty much it.
"We certainly got loads and loads of possession and we're just not doing enough with it at the moment."
The defeat left Jersey second-from-bottom of the Championship heading into Christmas, but the losing bonus-point moves them one further above Ealing Trailfinders in the relegation battle.
Meanwhile, Moseley's victory, their fourth of the league season, lifted them above Bedford and Nottingham into eighth spot.