On the Romanian Front, German troops seized Dobric. German army airship LZ.86 was wrecked while landing at Temesvar after a bombing raid on a powder factory at Bucharest. German seaplanes carried out a bombing attack on Constanza.

On 4 September, on the Caucasian Front, the Russian offensive continued south of Elen River, west of Trabizond. In Armenia, British armored cars of No.2 and No.3 Sections engaged Turkish forces west of Lake Van. Later in the month the cars were withdrawn to Kars.

On 5 September, in the Baltic Sea, a German airship carried out a night bombing raid on the Russian naval air station at Papengolm on Oesel Island. In the darkness 22 bombs fell into the sea.

On the Southwest Front, the Russians were advancing southeast of Halicz.

On the Romanian Front, Bulgarian troops forced a bridgehead at Turtukaia. A Romanian counter-attack broke the Bulgarian right wing, taking several thousand prisoners and much equipment, but they suffered heavy losses. German aircraft and an airship bombed the capital of Bucharest, while other aircraft bombed Piatra, Ploesti and Constanza.

The Central Powers granted Polish autonomy in an effort to influence Polish support.

On 6 September, on the Romanian Front, the Romanians were forced to retreat from Turtukaia towards Silistra. von Mackensen's forces struck further east in the Dobrudja, at Bazargic, and forced the Romanian 19th Division to retreat. In heavy fighting the 17th Division was almost wiped out, many being captured. The 19th Division managed to effect a junction with remnants of the 9th Division and fell back towards Caraomer.

The entire Romanian southern flank was endangered. The Romanian High Command rushed the 2nd, 5th, 12th and 15th Divisions through the mountains to join the 9th and 19th Divisions in defense of the Dobrudja line. Zaionchovskiy's Russian Special Corps had three infantry divisions, one cavalry division, and one division of Czechs and Slavs (former Austrian-Hungarian prisoners of war).

In the Black Sea, three Russian destroyers laid 220 mines near Kara Burnu to block coal ships route to the Bosporus. The Germans ordered submarines at sea and in Varna to avoid the Bosporus until a route could be cleared.

At Pless, von Hindenburg and Conrad von Hotzendorff (his Austro-Hungarian counterpart) signed an agreement which finally achieved a unified command of Central Powers forces in the East. Bulgaria and Turkey signed the agreement later in the month. The Germans ran the show.

On 7 September, on the Southwest Front, Russian forces captured Halicz on the Dniester River.

On the Romanian Front, the Romanians briefly occupied Orsova on the Austro-Hungarian side of the Danube. Bulgarian forces took Turtukaia in the northern Dobrudja, seizing 28,000 prisoners, but suffered 7,800 casualties in heavy fighting.

In the Black Sea, Russian torpedo boat destroyers Bystryi and Gromkiy opened gunfire on the Bulgarian port of Balchik, destroying harbor facilities and sinking twenty five barges loaded with corn. German seaplanes attacked the Russian ships without success. Flights of German seaplanes bombed port facilities at Constanza and Russian vessels in the harbor, causing minor damage, and losing no aircraft in the effort.

On 8 September, on the Romanian Front, Romanian troops began evacuation of Silistria on the Danube River. Russian and Romanian ships covered the withdrawal and shelled the city as German and Bulgarian troops moved in to occupy the city. The German 9th Army was concentrated at Mülbach in Transylvania. The Austro-Hungarian 1st Army, headed by General Arz von Straussenberg, covered the line on the Maros River.

In the Black Sea, a German submarine shelled the town and harbor works at Mangalia on the Romanian coast.

On 8-9 September, in the Black Sea, three Russian destroyers laid 240 mines northeast of Varna, with one of the destroyers being severely damaged by two mines off Constanza harbor.

On 9 September, on the Romanian Front, five Romanian Divisions concentrated along the Danube between Turtukaia and Rustchuk, prepared to secretly cross the Danube at Flamanda. By the evening of the 11th, the 10th Division and most of two others had crossed the river.

In the Black Sea, nine Russian transports landed troops at Constanza. Eventually there would be thirty six Russian infantry and eleven cavalry divisions, about 500,000 troops serving on the Romanian front. The entry of Romania into the war considerably extended the Russian front. Should the Romanians be defeated, some 400 km of the Russian southern flank would be exposed.

On 10 September, on the Romanian Front, German and Bulgarian forces took the fortress of Silistria, the second Romanian fortress in the Dobrudja region. Eighteen German planes raided Constanza, where Russian troops had disembarked the previous day.