NFL Week 18 Best Bets (Predictions for Ravens vs. Steelers, Seahawks vs. 49ers)

For the final time in the regular season, the SI Betting team has a pair of against the spread picks for this weekend's action, and there is a ton at stake in the playoff picture.

The AFC North, NFC South and NFC West will all be decided this weekend, and the No. 1 seed in each conference has yet to be locked up, making for a ton of intrigue in this regular season finale. So, why don't we place a few bets on the biggest matchups?

Each week, SI’s Peter Dewey and Iain MacMillan share their favorite bets for Sunday’s games every week, and we're coming off three straight perfect weeks, including two underdog wins with as the Philadelphia Eagles (+1.5) and Miami Dolphins (+5.5) both won outright in Week 17.

There's just one week left of regular season football, but we're looking to close it out with yet another perfect showing.

This week, we're eyeing two of the marquee games on the slate, as Dewey has a pick for the Seattle Seahawks-San Francisco 49ers matchup on Saturday night, and MacMillan is eyeing the Sunday night matchup between the Baltimore Ravens and Pittsburgh Steelers that will decide the AFC North.

Here's a breakdown for each of these picks, and their latest odds, for Week 18 of the 2025 season.

NFL Best Bets for Week 18

Odds via DraftKings Sportsbook and Caesars Sportsbook.

Seattle Seahawks -1.5 (-112) vs. San Francisco 49ers – Peter Dewey
Pittsburgh Steelers +3.5 (-113) vs. Baltimore Ravens – Iain MacMillan

Seattle Seahawks -1.5 (-112) vs. San Francisco 49ers – Peter Dewey

Seattle is a slight favorite in this regular season finale, and it has a chance to lock up the No. 1 seed in the NFC with a win.

Since Mike Macdonald took over as the Seahawks' head coach, they have lost just two games on the road (14-2), and there are a lot of signs pointing to them winning this matchup.

Yes, San Francisco has not lost since Brock Purdy returned to action, but the 49ers have relied heavily on their offense, which won't be easy against the No. 2 defense in EPA/Play. San Francisco failed to reach 20 points in the first meeting with Seattle this season (Purdy played in that game), and the 49ers have lost a ton of key pieces on defense, including Fred Warner and Nick Bosa, since then.

Overall, San Francisco is just 24th in the league in EPA/Play defensively. While I am worried about Sam Darnold in a big game, he did turn in a terrific performance in Week 16 against the Los Angeles Rams to set Seattle up to earn the No. 1 seed in the conference.

I'll bet on him to finish the job as the 49ers' offense can only take them so far.

Pittsburgh Steelers +3.5 (-113) vs. Baltimore Ravens – Iain MacMillan

It's time we accept that the Baltimore Ravens aren't as good of a team as the betting market continues to evaluate them as.

Entering the winner-take-all game against the Pittsburgh Steelers, Baltimore ranks 13th in the league in total DVOA and 12th in Net Yards per Play.

Just a few short weeks ago, the Steelers not only beat the Ravens in Baltimore, but they outgained them 6.2 yards per play to 5.5 yards per play.

Sure, the Ravens may find a way to win on Sunday night, but I will jump all over the chance to take the 3.5 points with the Steelers in what I believe will be a close game that comes down to the wire.

Odds refresh periodically and are subject to change.

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