30 home runs for 2 teams in one season.

Through 2018: 33 times a player has hit at least 30 home runs in a season playing for multiple teams. Mike Piazza is the only one to have hit 30 playing for more than two teams: in 1998 Piazza stopped in Florida for a week on his way from the Dodgers to the Mets but hit zero home runs for the Marlins. Gus Zernial is the only two team player to hit zero home runs for one of his teams.

Fred McGriff and Jay Bruce each did it twice.

Sorted by total home runs:

qry30HR2teams

playerID	yearID	First	Last	HRtot	ABtot	Team1	HR1	AB1	Team2	HR2	AB2	TeamNum
mcgwima01	1997	Mark	McGwire	58	540	OAK	34	366	SLN	24	174	2
martijd02	2017	J. D.	Martinez	45	432	DET	16	200	ARI	29	232	2
vaughgr01	1996	Greg	Vaughn	41	516	ML4	31	375	SDN	10	141	2
justida01	2000	David	Justice	41	524	CLE	21	249	NYA	20	275	2
dunnad01	2008	Adam	Dunn	40	517	CIN	32	373	ARI	8	144	2
fieldce01	1996	Cecil	Fielder	39	591	DET	26	391	NYA	13	200	2
beltrca01	2004	Carlos	Beltran	38	599	KCA	15	266	HOU	23	333	2
leeca01	2006	Carlos	Lee	37	624	MIL	28	388	TEX	9	236	2
machama01	2018	Manny	Machado	37	632	BAL	24	365	LAN	13	267	2
mcgrifr01	1993	Fred	McGriff	37	557	SDN	18	302	ATL	19	255	2
gosligo01	1930	Goose	Goslin	37	584	WS1	7	188	SLA	30	396	2
ramirma02	2008	Manny	Ramirez	37	552	BOS	20	365	LAN	17	187	2
bruceja01	2017	Jay	Bruce	36	555	NYN	29	406	CLE	7	149	2
finlest01	2004	Steve	Finley	36	628	ARI	23	404	LAN	13	224	2
kinerra01	1953	Ralph	Kiner	35	562	PIT	7	148	CHN	28	414	2
cespeyo01	2015	Yoenis	Cespedes	35	633	DET	18	403	NYN	17	230	2
uptonju01	2017	Justin	Upton	35	557	DET	28	459	LAA	7	98	2
kempma01	2016	Matt	Kemp	35	623	SDN	23	409	ATL	12	214	2
soriaal01	2013	Alfonso	Soriano	34	581	CHN	17	362	NYA	17	219	2
bruceja01	2016	Jay	Bruce	33	539	CIN	25	370	NYN	8	169	2
teixema01	2008	Mark	Teixeira	33	574	ATL	20	381	LAA	13	193	2
zernigu01	1951	Gus	Zernial	33	571	CHA	0	19	PHA	33	552	2
piazzmi01	1998	Mike	Piazza	32	561	LAN	9	149	NYN	23	394	3
bayja01	2008	Jason	Bay	31	577	PIT	22	393	BOS	9	184	2
bondsbo01	1978	Bobby	Bonds	31	565	CHA	2	90	TEX	29	475	2
burnije01	2003	Jeromy	Burnitz	31	464	NYN	18	234	LAN	13	230	2
sauerha01	1949	Hank	Sauer	31	509	CIN	4	152	CHN	27	357	2
rolensc01	2002	Scott	Rolen	31	580	PHI	17	375	SLN	14	205	2
mcgrifr01	2001	Fred	McGriff	31	513	TBA	19	343	CHN	12	170	2
guilljo01	2003	Jose	Guillen	31	485	CIN	23	315	OAK	8	170	2
johnsch04	2000	Charles	Johnson	31	421	BAL	21	286	CHA	10	135	2
batisto01	1999	Tony	Batista	31	519	ARI	5	144	TOR	26	375	2
cartyri01	1978	Rico	Carty	31	528	TOR	20	387	OAK	11	141	2